MK3 2.0 8v 113bhp 0-60 9.9 seconds, top speed 123mph. MK4 2.0 8v 113bhp 0-60 10.2 seconds, top speed 121mph.
MK3 2.0 16v 148bhp 0-60 8.1 seconds, top speed 134mph. MK4 1.8t 150bhp 0-60 8.2 seconds, top speed 134mph
MK3 2.8 vr6 12v 172bhp 0-60 7.6 seconds, top speed 139mph. MK4 1.8t 180bhp 0-60 7.6 seconds, top speed 138mph
MK3 2.9 vr6 12v 188bhp 0-60 7.1 seconds, top speed 146mph. MK4 2.8 vr6 24v 4motion 201bhp 0-60 6.9 seconds, top speed 146mph.
I'm not really seeing where the whole MK3 being slow or being a boat thing comes from, as in my opinion, with like for like bhp figures, the MK4 is no faster.