E46 is way faster than a standard GTA.
Even the previous M3 coupe is faster, but the previous model M3 convertible doesn't appear to be, being much heavier.
A 328bhp Autodelta GTA is easily faster than a standard M3 in a straight line, and closely matched on cornering speeds, if not finesse.
A 3.7 super is fairly closley matched with the really excellent lightweight E46 M3 CSL if both cars are on PS Cups or eqiuvalent.
The GTAs torque can really catch out the CSL in certain situations , but fast direction changes are the CSLs forte.
Sort of a conflict of brute power versus beautiful balance
The faster the circuit the more it suits the 3.7 GTA I think, over 100mph its clearly a lot faster, but the average speed of any circuit is way below that and briute accelerataion really doesn't count for that much on track.