would u guys recomend cutting a hole in the windshield of my ST to keep it cool? or would more dirt get into it and ruin the car? i have an air compressor with a blower hose attachment so im not worried about dirt all over the chassis and whatnot

yes definately cut o hole in the windshield. It helps so much. It was the first thing i did when i got my evader. Not alot of dirt enters through the windshield unless your trailing behind a truck throwing dirt at you, most of the dust and dirt get thrown out the back by the tyres so it is definately worth doin cause u get a fresh supply of air past your engine head and into the carb.

Ohh yes definately. This helps the engine stay cool gets cooler air to the air filter and when bashing extremely hard it really keeps the engine cool.

how big of a hole? the whole thing or just on the left side where the engine is?

depends on what want you can do 1 side or the whole window, or even drill holes with a small drill bit. whatever you want. but if you want maximum ventilation with the body on. then cut the whole window out.

Does your mill get too hot now? If so then by all means, cut a hole. If your engine is running at the right temps now, then why bother.

Usually just an oval on the engine side of the truck is adequate. I also usually cut the driver side window out too, for refueling, and added airflow.
Remember to radius your corners...square holes crack. It isn't a bad idea to re-inforce some of the more crack prone areas with shoe-goo, also.

to keep dirt out when running out mesh screen on the windows. more air less dirt

I agree 110 %

I guess so...
But, wouldn't you agree that you could get more performance out of whatever engine is in whatever ST by getting better airflow to cool the engine better, allowing a leaner carb setting?

Not really. Just because the engine is running cool, doesn't mean it's OK to lean it more. Overlean, is ovelean regardless of engine temps. It's kind of a less extreme version of what people see when running in the winter. In the winter, I have to fight to keep my engine temps over 200 by wrapping all kinds of stuff around my engine. Although my engine doesn't even want to hit 200, I still know it is properly tuned, by performance, sound, smoke etc... if I were to lean it out simply because it isn't hot, I would wear it out much faster than I should.

That is why most people will warn you to tune by performance, sound, smoke, temperature and feel, rather than temperature alone. Running too lean will kill an engine regardless of temperatures. Also, running an engine to cold will kill ot prematurely regardless of fuel/air mixture. Tuning/Maintaining a little high performance nitro engine is a balancing act between proper air/fuel mixture and proper temperature.

If your engine is running with a good temp and tune without a hole, then why bother. Cutting a hole, weakens the body, allows additional dirt to get in, and if your engine is running at optimal temps without the hole, then it may run too cool with the hole. I have a trx 2.5 R in my rustler that I have a hard time keeping up over 200. If I run my new CP body, which has no holes and covers up the car real good, then I can just get the temps over 200 consistently. If I put the stock rusty body back on it, which has a hole in the windshield and is cut up much higher on the sides, the damn engine wants to run around 170-190, which is a bit colder than I want it to run, so in my case, I want the body to cover as much as possible.