[email protected] Sean Morley's kit for "More (ly's) Muscle"
The Stage 1 Dynojet kit doesn't seen to do-well, the Dynojet Stage 7 kit works with a
full (complete) aftermarket exhaust, and a bit of tuning to ensure it's working as it should be. The Morley's Muscle is better for normal use, it has a good midrange increase instead of a top-end balance with less-satisfactory midrange. Exhausts need to be larger header pipes to take advantage of the different jetting, and a less-restrictive (read, 'louder') canister or two. The complete system 4/1's usually work best at the strip, the 4/2's are good for being a bit quieter (two mufflers instead of one).
Sean Morley can also sell you a Mark's complete exhaust, I think Mark isn't making a 4/1 now, just the 4/2, check with Mark's Exhausts or with Sean Morley. Star Rider Performance is Mike Lees, who is operating on his own after being with UFO Performance (Jon Cornell, deceased) and they have a variety of ear-splitters (Quad-Zilla (4-into-4) and Dragstar (4-1) and some more-quiet ones (4-2) but they're all pretty-loud. VooDoo is similar to what was UFO. Delkevic has a number of offerings.
You need to understand that without the larger 4 header pipes (and whichever end(s) you choose), the jet kit is not what you want. It's like marrying a pair of Siamese twins: they gotta go-together. I suggest if someone suggests Cobra 4-into-4's that you politely decline their advice, and choose another shop. Why? I'll leave you to use the 'advanced search' in the upper right-hand corner, for 'Cobra' "Cobras' or 'Cobra exhaust'.
I forget where you are. If you add that below your screen name, I won't need to keep-asking. Usually the USA market bikes, unless the bike was sold in Denver CO or a similar altitude or higher, main jets are 152.5 Mikuni. You can probably go to 150 or 147.5 Mikunis, and the bike will run-better, with a full exhaust, assuming you aren't 'way-above sea level. Be aware Dynojet main jets have a different #ing system than Mikunis. 'Advanced search' for info and charts.