IMPORT TUNER CHALLENGE

This is another of the achievement that gets easier like all the other time attacks. The easiest way to knock it out , is to play the time attack after you've learned the game and beaten a couple of bosses, at that point you're car should have a good amount of speed and control that you can knock this out with time to spare. Chose that car, run the course well (you don't need to be perfect). And the achievement will be yours. It's a longer course, so again you'll want to learn it ahead of time, but there should be more time left over than the shorter courses.