I just installed the K&N FIPK part no. 57-3017-2 for my 96 Blazer after reading suggestions on this board and am happy with it so far, I paid about $240 off ebay from this guy:
http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW
I can't vouch for the improved gas mileage yet since I just got it but I notice a little bit of difference in throttle response when I step on it, and it sounds cool too heh. My next investment will be an exhaust to compliment it.
-Drew