I was thinking of buying a WE M4 CQB-R (Gen-3) GBBR and would want it to be an all around gun, I found this product (
http://www.ts-custom.com/detail.php?id=11) on this site (
http://torontoairsoft.com/product.php?id_product=568), that lowers the fps and the gun is then usable in CQB. My question is: Does this product reliably and consistently change fps, or will it not work at all and I would of just wasted money?