The MSM is a fantastic overall package. 3k miles on mine and not one issue. I absolutely love it. I completed a road trip from Boston to Baltimore 2 weeks ago with the wife and the car was superb. Lots of mods available and Shiv from Vishnu Tuning is making serious progress on a 300 RWHP street-legal tuning program.
http://www.mazda-speed.com for more information!
A serious bargain for the 05 models. And as for the 06, I don't like it as much. Seating position is bit better, but visibility is a bit worse. I also don't like the interior materials. They are supposed to be resolving some issues with the MSM version of the 06 model and releasing later this year or early Spring.
Expect ~240 HP
