When I was building killer Yamaha 5mm mod engines way back in the day I ran a few systems then, MRD fuel injection, Pro-tec Mo flo's, and the infamous Boswell's. It wasn't until we started racing limited and Superstock Seadoo XP's that I used these 1st generation Buckshots (I still have a set for my ex seadoo race boat) and they worked very well for me, then Andrew changed to the newer NOS nozzles and I didn't think that they worked near as good on the Seadoo's! I did use the NOS nozzled Buckshot on some Superjet stroker mods for racing and worked pretty good, but aren't worth a crap for freestyle/freeride engines. What their worth? Don't know... this is the first I have seen any around for last 10 years! They might work good on a very well setup Yamaha engine on race fuel compression. (I never used them on pump gas)