which one
 

well my car currently has a nice flowmaster catback on it...sounds real good n all but i want to make it louder w/o doing a mid pipe right now (will do eventually) so i am just gonna change the mufflers out....my choices are flowmaster 1 chambers...or the slp shotgun's

why spend money on that if you are gonna do a mid pipe later on? just save up get the mid pipe and if it still isnt loud enough then change it out. The stock cats hold alot of power and sound in them, you will be surprized how much louder a off-road is. this is just my thoughts on it. You might not like how loud it is if you put on 1 chambers or slp then do the mid pipe.

Yea, just save for the midpipe. By the time you get the mufflers, and have them welded in, it will be just as if not more expensive than the midpipe.