Went out and test drove a model year 2004 BMW 325i. Similarly to other test drives I have done before for other cars I left feeling great about my RX8. Our cars are better than the 325 in almost every way. Except for the brand (if you care) and the awesome I6.

The I6 rated at only 184 hp is probably one of best engines I have tested before (not that I have tested many higher end cars). It is very smooth and powerful. At times I could swear it pulled stronger than the Renesis even with 2 people in the car. The kick it provides at midrange is almost turbo-like compared to the linear feel of the Renesis yet it is very smooth. If the Renesis has 220-232 hp at the crankshaft it puts about 180whp on the ground assuming a 20% loss transmiting the power to the wheels. Maybe the 325 GAINS power in transmission? Overall, I would probably prefer the Renesis due to its lighter weight and high redline IF it had the same mileage and reliability as that I6.

Other than that the RX8 is a clear winner in everthing else including:
- balance and feel (after all this is a light weight sports car)
- handling by a huge margin
- clutch and shifter (the shifter is not as precise and is a long throw type. The clutch pedal is weird. It engages when the pedal is almost fully released)
- steering response
- throttle response
- brakes
- interior plastics (that 325 did not have wood trim. The plastics in that 325 looked dated, almost '80s like)

Compared to a 325, an RX8 feels much more responsive to driver input and feels much better planted to the ground, a clear winner. That said I would have had to think long and hard if a similar I6 were available in the RX8. The 325 is a well put together RWD car with an awesome I6 but overall is probably overpriced.

I've driven a good amount of 325's. I've also driven the 335i and newer 328i's as well, and even the 328i does not feel like it has as much pull as the 8 does.

The 325 is a well put together RWD car with an awesome I6 but overall is probably overpriced.

bmw's inline-6 is definitely a gem. e46's are indeed nice, and they're not overpriced if they're used and cheap ;) actually, even back in those days, a basic stick shift 325 was pretty reasonably priced (~29-30k)

One of my former co-workers had a 325i. Driving it was the biggest automotive disappointment of my life. Other than fuel economy, the 8 blew it away in just about every other category, and his car stickered for nearly $35k.

Also, as far as handling goes the 8 was a better BMW than BMW. By this I mean it does a better job of being firm and responsive but without harshness, which is supposedly the quintessential BMW trait. The RX-8 just does that better. It might be because the RX-8's suspension is much more advanced than BMW which still uses outdated MacPherson struts.

The thing I liked about the I-6 though was the smoothness and how consistent it felt at any speed. Accelerating from 70-90 felt the same as accelerating from 20-40. A lot of cars these days feel like they have a good amount of pull off the line but soon run out of steam at higher speeds. Although the 325 didn't have tons of power, it felt like the power it did possess was always ready to use.

BMW's inline6 is a gem in the piston world. Compared to the Renesis, it felt lazy and coarse especially at upper rpm ranges.