It is a Stage I unit (the most basic of several) and costs a little over $300.00. That sounds like a lot, but it is a very effective tuning tool. It will allow you to run significantly more boost than you could without it, and is a big help in preventing detonation. It's really easy to hook up, and I mean REALLY easy. For the street AND strip.
Check it out.
I see you are keeping an open mind on the drivetrain... and, that is very important. One fact to realize; the 904 has torque-handling capabilities well beyond what you will need. Just a word to the wise...
