My experience with High Speed Performance was very positive. I used them twice for tuning work on my 60’s muscle car. One visit was a chassis dyno tuning session after I installed several bolt-on HP upgrades. WHAT A DIFFERENCE! After four pulls, it was a different car in every aspect: response, acceleration, no bog or lag, etc. The shop is very crowded, and the lobby almost non-existent, but hey it is a hard core garage and not a new car dealer. Nice guys, too.