I built one of those DIY PnP megasquirts the very first time I built a kit. It was about 400.00 w/ all of the stuff to check the build. ( another kit called a "stimulator"). I opted for the 4 bar map sensor, the boost controller, and the various tuning cables. I'd say that the kit is a 7-8 out of 10 on the difficulty scale to build, test, and program. Although everything is there to help you build one of these kits, it does require a certain technical proficiency w/ a soldering iron, and a decent understanding of computers. Even though there is a base map from a late model 5.0 fox mustang to use, they still will tell you its up to you to do the fine tuning to get it right. You can buy it all assembled, and ready to go as well, but it is more money, (like a couple of hundred dollars more.) Regardless of which way you go, you will still have to fine tune it after start up. This current car I am building another MSII kit for it. I started on it, but w/ all of the stuff there is to do on this car, I just put all of the stuff back in the box, for another day.