what air filter should i get to kepp out sand on my gt.

a paper k&n looking like filter is good because it repels sand thats what i have on mine with a spung prefilter, or a motor saver airfilters are good.

no K&N filter is good...they are the worst air filter you can buy for a rc motor!!!!!!!!!!!!!! They were designed to be a breather filter for automotive applications
Use a foam filer with a foam pre-filter...make sure you use good air filter oil
Motor saver is you best bet, that's what I run on my trucks. I also use the dust/mud cap when track conditions are bad

it depends if you have a slide carb or a rotary carb? the rotary carb is smaller
here is the AE one and i was told it works great-
http://www2.towerhobbies.com/cgi-bin...?&I=LX3408&P=7

so a search for "air filter" on tower

Motor saver works good for me.

i would go with www.rbinnovations.com air filters there really good and they look good

I use a GPM two stage. It has a paper iner with foam outer, Good http://www.hobbyetc.com/cgi-bin/cata...m&lim=0filters