Interesting..!!
Having both a very well sorted 3200 AC Auto and a 4200 CC, if I am honest they both have really good characteristics. The 3200 is manic when the turbo's spool up, but I suppose by then the 4200 has a slight head start, having slightly more power at the initial take off. Both interiors are excellent, both have good brakes, both have great roadholding and cornering ability. The 4200 (facelift) has excellent stability at any speed and if anything feels slightly better planted on the road at high speed than the 3200, only slightly. It depends on the year of each model I suppose and if you step up to a GS then it is a slightly unfair comparison. The later the car for each model, the better the performance is overall. I love driving both as they have differences which you can enjoy.
At the end of the day if you can drive well and quick, you will find a way to make any car sing an excellent tune.
I would have one as a daily car, no question.