[nonovurbizniz]

a cable tranny is one which the throwout bearing is well... thrown out via a cable going from your clutch pedal to the tranny (it engages the clutch). It opperates identically to your gas pedal cable.
A "Hydro tranny" is one in which the clutch is engaged via hydrolic pressure created by a master cylinder No not your brake master cylinder it's another one. that's the easiest way to tell. If you have 2 brake fluid looking containers your tranny is Hydro.

another way to check is if you are looking at your engine from the front. the tranny is to the left. if there is a metal arm with a throttle cable coming off of it you have a cable tranny. if there is an odd looking protrusion with a bleeder valve on it then you have a hydro tranny.

FINALLY

everyone here says why go with cable hydro is where it's at blah blah blah.

B.S. Cable is way better it's faster you have much better pedal feel. you don't have to worry about:
1. a master cylinder (they go bad they leak the run out of fluid etc.)
2. Pressurized line ( it rots it leaks it can go bump and snap.)
3. the weight while negligable and I hate it when kids on here talk about stripping this and that for weight... It's still there 10-30lbs (total guess it's gotta be at least 10lbs though)

So if it save money (ie you already have a cable tranny.) then do it. HOWEVER if you already have hydro DON'T switch to cable it's not worth it. the simpler you can make any project the better.
And remember that 100 bucks dif. between a1 and a2/3 is taken right back up by a hydro to cable conversion on the a1 if you have to do it.
But if you have a cable tranny I WOULD NEVER EVEN CONSIDER swaping in a hydro unit. It's way too much of a pain in the ass so unless it means you get LSD or the engine you want doesn't have a cable tranny stay with what you got.