The beauty of LMPs is that they come with all of the "fully customizable" stuff installed. Throttle control and driving technique are most important but a great tune can go a long way to even improving your technique, let alone your lap times. High power, lightweight cars such as LMPs benefit from having the low (re: useless) gears set shorter, numerically lower and thus to the left on the slider. When you spread your gears properly you can end up solving most of your wheelspin problems provided you still maintain decent throttle control. The LSD is also absolutely invaluable, have a look at the in-game help section in the LSD tuning menu for information on how it works. Hell, even suspension controls how a car puts the power to the pavement. My most important tip would be to USE THESE FORUMS! The tuning section has helped me many times without even using the tunes. Just seeing how people addressed certain issues helped me work tunes myself.