The BMW has terrific quietness. Compared to my CSVT, it's virtually silent. The ride is firm (I got the sport package, so it's not wobbly like some luxo-barges) but it's very comfortable. It is so quiet compared to what I'm used to, that I immediately bought a high-end radar detector. Failure to use cruise in the BMW usually results in at least 15 over the speed limit. It's that quiet.
The 325 is substantially similar in performance to the SVT Contour. On paper, the CSVT has about 16 HP over the 325, but the continuously-variable valve timing on the BMW seems to compensate. The lack of a distinct power band is interesting. On the SVT it really kicks in at 4000 rpm, but on the 3 it has cojones at all rpm.
The transmission on the 325 is a Getrag, same brand as the one used on the SVT Focus. It beats the hell out of the MTX75 on the SVT. Shorter throw, better synchros, but the same gear ratios. The clutch is also a lot smoother than the Ford's. The Dynamic Stability Control and traction control make the BMW surprisingly hard to get out-of-shape in.
Visibility is a bit better in the CSVT. On the 3-series coupe, the b-pillar is right in your line of sight when checking your blindspot. Some of this might be that I'm unused to the BMW, versus 6 years in the Contour.
My CSVT has the full Koni/BAT suspension, plus strut tower braces, etc. The ride is deliberately harsher than average but it has helped the handling. The BMW on the other hand rides much more easily, but I think it will beat the CSVT in the twisties. 50/50 weight distribution and RWD really help.
By no means am I giving up on the CSVT, though. The wife now uses it as her daily driver, and she's quite stoked about it. With the 17" Koseis and the lowered BAT kit, my CSVT gets plenty of looks.
In the final analysis, the BMW is "nicer" than the Contour SVT, but performance-wise, they're pretty close. I like both. The biggest disadvantage to the BMW is obviously cost. For example, the dealer wanted $900 to include the 6-disc CD changer. I just installed one myself for a whopping $350 (and they're both made by Alpine, so mine fits in the slot but also plays MP3s...)
I'd like to get license plates that have the acronym for "I Am Not A Lawyer" but that might lead to confusion...