It can be done,but not worth the cost. From 97-99 Porsche used a regular style throttle cable,from 00+ they used what's known to be called e-gas,which is basically an electronically controlled throttle. You would have to take the entire throttle assembly from the 3.2 along with everything else which basically isn't worth it. The 2.5L tranny should be reusable,but I'm not 100% sure(3.4L match up to the 2.5L tranny).
If you going to put a 3.2L might as well make a 3.4L(or 3.6L) because the cost shouldn't be much more.
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-99' Zenith Blue 5-spd...didn't agree with a center divider on the freeway
-01' S Orient Red Metallic 6-spd...money pit...sold to buy a house