Getting the rest of the T II swap together...
 

In the next day or two I am going to be checking out a S5 turbo: diff, ECU, and Half Shafts. I am not sure how to determine whether or not the parts are in good condition. it would be awesome if you could trust every random person you buy parts off of, but i'm sure you guys know thats not always possible. If you have any pointers, i would appreciate it, pictures help :) thanks

Driveable differentials on these things are getting more rare each day. Rotate it by hand, open up the drain or filler plug, stick your finger in it. Check the fluid's viscosity, smell, color, and look for small metal shavings or any other odd foreign pieces. Also, check for leaking around the pinion and output shafts. If you're wanting to know if it is for sure a TII differential, I'd just bring my TII driveshaft with me and make sure it bolts up to the differential. Pretty easy.

For the CV halfshafts... You can verify they are TII as long as you have verified the differential is a TII differential. (Halfshafts bolt up to it.) - As for functionality, be sure the movement at the dust boots is smooth. Check the dust boots for leaking, cracking, loose band, etc... Check each shaft for warpage/bending, cracking, rust, etc... Be sure the splines aren't damaged, either.

As for the ECU... It may be hit or miss. If you have another S5 TII to test it on, go for it. I'm not really sure of any specific ways to test the ECU's.

Got my diff, ecu and half shafts yesterday. all appear to be in good condition, hopefully picking up the motor, tranny, driveshaft, some intake parts. gonna use my new corksport downpipe that i bought for a different motor swap that needed it. wish me luck!

I'm also doing a TII swap but it's an s4, good luck, post pics of the progress!