the KLX pipes that BG makes do not have any functionality problems. there has been one documented case here that surface rust appeared. they fit like a glove and make loads of horsepower which has also been documented here with a dyno report. the BG is a good system in spite of what the minority people say here. we who have it know that it is a major shot of adrenaline for the 250 and it fits better than oem. at least the BG doesn't take a weak 1" spacer just to get it to mount up. I would call it a bargain if he just paid $310 just for a slip-on and I got my whole system for $390.

I might add that the 2 bros. pipe is real nice and i'd bet it fits well, their products are excellent and that pipe is made exclusively for the 250S- that's good. but remember to get a longer chain if you want that 45-tooth sprocket to fit. trust me, you have to. kudos for getting a rare pipe. i think the wait will be worth it.

 

well vibrated bolts isn't no big deal. loctite them.

 

it's all personal preference. but if you are going to bore it later on, you need a full system. none of those slip-on noisemakers will do when you bore it. plus, judging from some of the costs people are paying for slip-ons, a full system is a better value. if you want the absolute best fitting system, BigGun can't be beat. I have one and love it and have had no problems other than a couple vibrated screws out the back which BG replaced free- but one guy on here has one and has gotten surface rust where it shouldn't have because they have a ceramic coating that's supposed to prevent rust. one good thing about the BG is the header stays shiny chrome at least mine has and won't discolor; unless it rusts i guess. Muzzy makes a good system too, it's fully stainless steel and will not rust. drawback is it discolors immediately and there are some minor fitment issues with it including rubbing the rear passenger footpeg. guys are taking their peg off and grinding it down and saying that corrects it. there really aren't any more full systems out there that don't cost both your arms. staintune makes one but imo it's really ugly and is just a name and doesn't look like it belongs on a dirtbike. you can also buy a fourstrokeworks header pipe ($140 or so)and your choice of slip-on. research research. that's the fun of it.