I may be a little late to the show on this one.

But, I have the megasquirt PNP2 on my car. Well worth the extra money over trying to build it yourself in my opinion. The megatune software is simple to use and they have awesome customer support. I would recommend just getting the paid version of the software. The free version works fine. But for $80 it is well worth it in my opinion. I haven't had the car on a dyno yet so I was tuning on the street. The autotune feature in the paid software makes tuning on the street much simpler.