From a potential customer point of view also, instead of making everythin wider to fit the screen, just centre the pages. There's a lot of space down the right side that could be filled or the page layout altered for a better fit.

Simple white-on-black or black-on-white colours for writing make websites easier to read. Altho to be fair there isn't a vast amount of technical information on each page with a small font so that's not too much of a problem.

Maybe some more photos of your car: give the car its own page with tech spec and photos showing what work you've carried out. Can you also get a better photo cutaway turbo? The graphic doesn't quite look right.