[Henry Schmidt]

If I read your post correctly, an over-rev in a 3.2 puts the rod bolts at risk. The 9mm bolts are too small to handle high RPM let alone a substantial over-rev.
That said: 964 cams offer very little performance enhancement.
The exhaust is the easiest upgrade. 993SS cams are what we find to out perform most other cams with stock intake. If the engine is apart, IE: complete overhaul, custom 3.4 [98mm] pistons 9.8:1 compression, longer rods [3.2 Carrera rods are poorly designed and too short] equal length headers, sport muffler.
Combined with the proper chip and bingo. With these changes, if you later decide to upgrade to ITB, you're ready to go.

The longer rods increase piston dwell and reduce piston side loading. This simple [although costly] really frees up the engine for higher RPM.

We also rebuild the rockers with a resulting friction reduction in the valve train that reduces heat and parasitic lost. [free horse power]