To find GPM stuff easy go to ebay and enter "GPM MT2" (- quotation marks) as a search query and boom every GPM item will be brought up.

I find RCmegaoutlet is a pretty good seller on ebay I've ordered a fair amount off him and always get it fairly fast with decent shipping prices

Or you can use his site (just found a sticker he sent with my orders that has his link on it) [link=http://www.rc-mall.net/productlist_acc.php?brand=hpi&type=mt2&page=2]rc-mall.net MT2 stuff[/link] Page 2-6 is mostly GPM stuff

Personally I'd prefer ebay cause sometimes you can find it cheaper from other sellers