I m from JB, I did engine conversion, wiring and body kit few months ago in Taman Rosmerah JB. I think it's best to survey around before choosing a workshop. I took about 6 months to survey around JB, looking at how they work, getting the feedback from theit customer. Big busy workshop doesnt mean they do the thing nicely. Even the low profile workshop are sometime better as they give full attention to your car. Treat your mechanic as a fren, sometime I bring them KFC or buy them a drink. They are also human being. Sometimes they do mistake too. But the best mechanic is being honest to u and also say sorry when they did mistake.