I find this prob with some of the garages I've worked in, the boss wants to take on specialist work like performance engine rebuild when mechanics are only normally trained for standard stuff and they try it and fuck it. Best to use the well known engine builders if u can't do it yourself and most normal indipendant garages aren't skilled for that kind of stuff but some will take it on thinking they can make a quick buck on it. If I weren't a mechanic I could never afford to run my Cossie if I had to pay someone else to do the work