My 02 cents. I'm by no means a bike mechanic. My experience though in engines, tuned pipes, and headers does say something I think., I've seen some pretty remarkable changes in HP on those items, No.1, if a bike is broke in gently, it will not be a fast as one that was broke in hard and fast. I've seen undeniable proof of that, many many times!! What makes a bike with 4 in 1 and headers, broke in fast with good tight cylinders and pistons faster? Horsepower. I've seen several times, several bikes, leave others behind quarter mile 10-20 car lengths? Same weight and same experience rider. No 2. I fly RC airplanes using 2 stroke engines using 15% nitro. Engine was a size .32 OS max from Japan. I found that engine with a certain type of tuned pipe could outperform a .52 engine with standard muffler using 30% instead of 15% nitro!!. So, certain types of 4 in 1 do better, make more HP than others. That tuned pipe on that little .32 engine had to be EXACTLY a certain length and diameter. Some 4 in 1 exhaust makers I know have to be different in some ways right? Length, diameter maybe even how many twist, turns and the angle of said header. Most buy 4 in 1 sets because of looks and sound. On my 2008 vet, I had to remove the Texas headers because of regs in Cali. When I went back to stock exhaust, big time difference on the pull! We had some sportbike boys in Baton Rouge, La that raced, tuned and overhauled their own bike and I would talk to them all the time. They all swore by a certain 4 in 1 maker and model of exhaust and swore on dynos that their pick of 4 in 1 made 20 more HP. So, yes if stock can make 185HP, a bike broke in fast, and with some types of 4 in 1 setups, power commander, AUX. fueling module, don't see why they couldn't make 200 plus HP.