I don't know of anyone locally who owns one, but from what I've read about them, they aren't too difficult. Wiring and installing the new crossmember seem to be the issues. When the added weight of a V8 is only 200 lbs., I have been seriously contemplating building on myself. They do sell the kits which make it easier, but I don't feel comfortable with the welding of the new x-member w/ my wire welder. Check out Monster Miata, (I believe that's where I saw the article) Great progress photos and explanations of the processes for the DIY.