Current:...
Front :  std ke25 strut/disk with kp61 Starlet hubs, 4x114.3mm stud pattern. This is a bolt in swap to convert ke25 4x110mm stud pattern on NZ models to 4x114.3mm. Front springs had 1-1/4 coils cut out of em but were still captive with the standard shocks.  This lowers the front about 25mm. That was until King Springs were fitted.

Rear :  Diff is from a '68 RT40 corona which is an 8bolt version with slightly larger axles than a 6" diff. Don't bother with this! But there's also a larger version with 6.62" D series 10bolt diff which will fit the 6.7" T series head.  To make the RT40 diff fit, the leaf mounts need shifting outward 10mm per side to bolt in. Jacking the leaf springs out could work temporarily but it'll eventually flog out the bushes.  There's no shock mounts on the rt40 diff as the corona has them mounted on the leaf retaining plates, so new shock mounts need welding on top of the diff mount like the original ke25 diff. (i never got round to doing this).  A ke26 wagon has the bottom plate shock mount like the rt40 so would be an easier conversion in a 26 wagon. RT80 era Corona diff is another option ie around 1370mm wide.

planning...
Diff:
I plan to use either a shortened toyota 'F' series 7.5 " or 'G' series 8" live axle diff with LSD. A third diff link mounted next to the driveshaft will form a 3-link for anti tramp. The sway bar mounts move to the chassis with the ends attached to the diff for better unsprung weight. There is an oem disk brake 7.5" which are pretty rare now, found in jdm spec Celica ra45, ta45 and Corona rt132 2000GT, or US spec ma46 supra. These have identical axle bearings as ae86 disk diff with a larger 10" disk. I'm running one in the ke70 drifter with great success. Rather than cut one of these up I plan to replicate it with either the 7.5" center, ma45/te71 ends and shortened Estima axles, or 8" center and custom axle bearing cups to suit double row bearing and 10" disk brakes.
Another option is the ms110/ ms112 Crown diff which have an internal drum handbrake and 260mm disk on some models.  The Crown diff are 5-stud 5x114.3 so the axles need redrilling to the corolla 4stud.   The locating spigot on the 5stud version are also larger 67mm diameter so be wary as the std corolla or celica rwd rims will not fit!   The crown diff will require shortening too as they're 1450mm.   I've had one of these diffs fitted in my KE70 done early 2004 and had to watch which rims used due to guard rub.  
Estima diff's are common and cheap. Downside is they're bulky and wide. At 1520mm? they're as wide as you can get. But this suits shortening them. The brakes are massive so a downgrade for better handling may be advisable. The head casting is bulky compared to earlier housings. Possibly not much different to an 8". A 7.5" F series live axle LSD diff head can be found in jdm cr30 masterace-surf or US ma46 supra and maybe a ra28 celica. IRS versions are found in GT spec jdm tt142, ta63, aa63, ra63 corona/celica/carina and ma61 etc celica-supra's which were optional from factory.  Altezza torsen lsd and aftermarket LSD's for altezza or any toyota 7.5" for that matter, will also fit with the correct side bearings.

Driveshaft:
Will use a shortened shaft using rebuildable yolks to suit the box and diff.. should keep costs down by simply shortening a std shaft. May be an old corona shaft with W50 box and T series diff as some of these will match W55 and the F series diff pinion flange.

Front Struts:
Plans keep changing but along these lines..
The lightest and simplest way apart from using original strut, is using ae85/ae86 coilover strut (which is a common upgrade for te27 owners), sitting atop te27 steering arms (bolts into a ke2#) with short stroke shocks and ke25/te27 camber plate to bolt straight into the ke2# chassis. The simplest option for vented disk is the std ae86 9" v disks/calipers/backing plates. But with the power i'm aiming for, something around 280mm vented with 4pot alloy calipers and custom caliper mounts to fit under 15" wheels will be preferred.

Another option is to use ma45 mk1 celicaXX strut with 10" solid disks which will bolt onto te27/ae86 steering arms (can use ae86 p/s arms 115mm C-2-C if te27 arms not available).  The mx73 cressida 10" vented disk/hub do swap across to these struts as the bearings are the same but the ma45 caliper is not wide enough to fit around the wider cressida vented disks (tho maybe with worn pads).  so a fabricated caliper mount plate required to suit new caliper, ie 4-pot calipers could be used.   This should theoretically give me a bolt in 10" vented disk strut with decent calipers (this weighs more than ae86 setup).

Option #3 to use toyota 10" vented disk/struts (ta63, cressida etc) but many geometry changes required to make work and they're not exactly light in weight. Best to use custom made steering arms as the shortest factory arms available for the 90mm strut (that we can find) are 125mm between centres from power steer ta63 celica/carina. Compared to the ke25 arms at 110mm.  Otherwise this set up would give an increased turning circle and slower steering response with longer steering arms.  
The downside of the larger struts is the added positive camber amongst other things so camber plates or longer lower arms etc would be required for ideal setup. Then the usual RCA's fitted when lowering the car substantially, short stroke shocks, urethane bushes throughout etc etc. 

Steering:
Rack and pinion!  The mounts for this can be welded onto the rear of the engine cross-member similar to an ae86.  This will also give more steering component clearance under the 4age's sump than the std recirculating-ball steering system and will have quicker lock-to-lock if the correct rack steering ratio is used.  Mods required would include modifying/adding universals to the bottom of the steering column since the rack input shaft would be in a different location.  Careful planning is required to make the steering geometry work successfully and local mod certification rules adhered to.  The toyota racks I've measured so far are all too wide.  The ke2# inner tie rod pivots are about 100mm narrower than most later model toyota's with racks.   KP61 starlet rack is possibly the shortest. If i did use one of these later racks it'll affect the toe as the suspension travels up and down (bump steer).  So i'm looking for a rack with the correct width between the rack ends.  The other option is to widen the control arm pivots which can be done by fabricating something custom or butchering a ke3, ke7, ae86 or kp6 engine crossmember using shorter lower control arms to suit. ie major surgery.

Brakes: lookin at using 11" vented disks up front with alloy 4pots and 10" disks on the rear with integrated handbrake calipers.  The downside is 13" rims will no longer fit.  For the brake master i'm thinking about an under dash twin master with bias bar mounted to a custom pedal box to shift the brake master cylinder out of the engine bay. (wiper motor moved). I had originally sourced a te27 pedal box, but it still does not give enough engine clearance for my particular setup.  After comparing a jdm te27 and the NZ ke25 pedal box, the brake master mounting holes are in totally different positions with te27 brake master mounted closer to the strut tower.

General suspension upgrades:
Will use Nolathane bushes all round.  Use strut bar on the front to lessen chassis twist..  possibly upgrade the front sway bar but do this once the rest of the suspension is finished.   The 7.5" diff has a sway bar mount already so will mount up a rear swaybar by adding some end links to the ke25 undercarriage.  (std ke25's don't have a rear swaybar).  To lower the rear I have sourced some reset leaf springs which are better (to reduce axle tramping) than using lowering blocks.  I'll then play with adding/removing leaves to stiffen the spring rate.  I'd like to also add some tramp bars because axle tramp (wheel judder) is a problem.

Wheels:  Will use jap 15" deep dish alloys.  Bought some Konig Rewind 15x7 for it till I know the offsets i can run with flares fitted. Will try get 9 wide in the rear. =)