Nightsters are just too different to have regular sportster parts work on them. With their special paint job nightsters are down 10 hp from other sportsters.
Seriously, the average for a Stage 1 on a rubbermount sportster is ~75 hp.
A start would be to upgrade your ignition system (module, coil) and then look at a set of cams. You probably should have gotten new pipes instead of slip ons.
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Ken in Western MD
2002 XL1200C
Buell Thunderstorm Heads and Pistons
Screamin' Eagle .551 Cams
Samson Caliber 2 into 1
94.5 HP
I'm not really qualified to get that specific. I think that they actually call them EFI controllers instead of ignition modules. Check out Dynatek or Daytona Twin Tec. As for cams, you'll need to decide whether you're looking for a high final HP number (at the expense of low end pull) or a bike that pulls hard early. My bike makes 94 HP but really at the expense of torque and my HP gains are mostly above 4500 RPM.
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Ken in Western MD
2002 XL1200C
Buell Thunderstorm Heads and Pistons
Screamin' Eagle .551 Cams
Samson Caliber 2 into 1
94.5 HP
In my opinion the best thing to do is call Dan at NRHS Performance and discuss what you want out of the bike performance wise. He is a great guy who really knows his stuff and also EFI Sportsters. His personal bike is a 07 883 converted to 1250cc that dynos at 102HP. Here's his website: NRHS Performance