I'm assuming there's been plenty of talk here about these vehicles - there were plenty on the S4 and 'Vette forums. (less so on the latter) I sold my 'stage 3', just a farcical way to say a B6/B7 S4 had all three: CAI, flash and full exhaust, S4 a few years ago. When I had purchased the S4 back in '05, it was down to the CTS-V, E46 M3, and the B6 S4. I've always been a fan of V8 performance, so when Audi moved to the 4.2, 40 valve V8... it was compelling - and the CTS-V? too crude, especially the interior, and the M3 seemed a bit too 'focused' on sport. The S4 received a CAI, a 93oct flash, and full exhaust (200 cell cat DPs, and non-res catback)... and no doubt, one of the most unique exhaust notes from all of my cars past, and present. I chose the S4 over the M3 since I wanted a car that would make the best DD, and again, I liked V8s - the car proved to be exactly that, a great daily driver with great overall balance: perfect interior ergonomics, overall driving dynamics, and understated style. I racked up on avg, ~24k miles every year in DC metro traffic for 3 years - great all around car, but not great at one particular thing, and toward the end, the driving feel seemed too 'sterile', and I started looking for something else.
Enter the '08 Corvette Z06 - wanting something that returned me to rear-drive dynamics, and more explosive performance. (note: I grew up with Mustangs (4), and I was loathe to pick up a Chevy
) The Z06 proved to be everything I expected, brutal/explosive performance (I have 345/20/20s out back and it breaks traction on accel at 80+), with heavy-handed handling dynamics... oh, and the low-rent, joke of an interior, with seats made for someone with 'more girth'. I figured the latter was going to be overshadowed with the focus on performance... but it's been 1.5 years and it irks me every time I get in the car. So having a combination of an Infiniti FX45/BMW X5 4.8is as the daily driver for about 2 years, I decided to find something that returned more 'usable' driving dynamics, and fun-to-drive factor to the DD. So, with BMW adding a V8 to the M3, I came full circle.
I recently picked up a 2010 M3 Coupe 6mt, which reminds me a bit of the 540i6 I had before the S4. Early impressions have been great... immediate handling responses, lively and agile - 'usable' handling for spirited daily-driving. Granted, I expected a bit more explosion from acceleration, but I still have the Z06 for that. The interior is sweet, and it's truly high on what you'd expect for a great-handling car with balanced luxury amenities. I'm glad to have such a real-world, sports car for my daily driving duties, and it's so much closer to the do everything well S4, but with better handling and performance - and I'm loving the heavily bolstered, seat! Far better than the Recaros in the S4, and not even worth comparing the shiet on the Z.
I'm looking forward to enjoying the E92 M3, and it reminds me that the performance wasn't enough to ignore the awful interior of the 'vette... I tried, so I'll hold on for another year or so and move on to a 911 TT as my halo car.