The Mazda RX8 is not a car for everyone as it has a 1.3L rotary motor in it. But if you are looking for a well balanced, excellent handling decent accelerating sports car then this is the one for you (although it's not a true SC since it's got 4dr). The best 0-60 I've done is 5.9sec launching at 5k and no roll out on Perli Zero's. The Renie motor more reliable then the 20B was, however do to no forced induction the motor losses a bit of tq and a few hp. But no need to worry as she makes up for it in the corners. This is a true lux sports car for a very well equipped price of 25k with heated seats 6spd man 6disc cd changer and many more options. Drive one just know the limits of the motor.
The styling of the RX8 is unlike any other car, although some claim it's a bit to busy I think it's just right. Almost all the body parts are meant for down force or some aero dynamic means. There will never be a 100% loved car but the 6spd man is wonderful. If you drive the Auto you will be less then thrilled and may have some motor issues on the Early models as you lose 2 ports from 6-4 ports. Not a recommended buy.
If you do want more HP and TQ buy a Greddy turbo kit (roughly 4g) and have it installed at Peter Farrel Super Sports in VA for about 1500-2000. I highly recommend these people ( I am no way affiliated with them) however in 2003 they worked on my RX7 and did a phenomenal job, fixing the issue the dealer spent 3 months on in less than a day. I do not recommend any more then 330hp pushed with 8psi from the RX8 on a stock motor.
You can't improve HP with and exhaust and intake, however if you want a deeper sound and better looks I recommend the change over. Mazda did an excellent job squeezing all HP out of the little 1.3L