944 suspension
 

I've noticed that an '86 Turbo seems to be the prefered suspension for GL's; why is that? Other than the narrowed track (compared to later years) what advantage does the '86 have?

That is the advantage, all the others you'll need wider fenders.

Are the brake components the same for an '86 and '87+ Turbo?

The rotor's are different, but e-brake shoes are same. The calipers are same (4 pot Brembos)

The calipers are not the same, '86 was a one year only. Although they look similar outwardly, the piston design is different.

Yes there are two different types of pistons, but the bolt pattern is the same. Here is a pic of the different types, and seals.

http://i52.photobucket.com/albums/g3...1.jpg~original
http://i52.photobucket.com/albums/g3...9.jpg~original

So I could put later calipers onto '86 bits?

Is there a significant difference in the braking effort provided?

There is one set of early aluminum arms that have NA bolt pattern, but the rest all have same turbo pattern.

Braking will be the same with both piston types. (they just have different type of seal set-up) But some models had different piston sizes on front, they could be 44&38mm MO30 option or 40&36mm. ALL rear turbo's have 30&28mm pistons. If your asking about braking with turbo vs. NA. Turbo is overkill for T1, but I like "the look" :D