Sean, the jetta body is fine. Just remember that if you are just driving it up and down a parking lot, your temps are always going to differ from those that actually race these cars. The only holes that are actually needed in a lexan body are those that you use for adjusting the carb, 2" hole in the front and rear windsheild. I do not even cut out any of the side windows for vent. Most of us that race use 30% nitro content. I did not shim nor change the glow plug using 30% nitro on this R-Spec. I realized that when I made the switch from a 20% to 30% that the temps on my RB's came down a bit due to the nitro cooling the engine down a bit. Besides it produced more power on the track. I gave up a little run time per tank with 30%, but it does not hurt when you have a good pit crew. Just keep in mind that you should use the low end needle to adjust for punch acceleration (timing) and the high end needle for power (temp control). If your car boggs a bit before it takes off, you could lean the low end a bit till it just blast off the ground. Then adjust the high end needle to readjust the temp settings during high speed runs. I usually just adjust the high end as the car is lifted from the ground at WOT till it sounds like it is at its best high rev.