I know stage 1 is upgraded air cleaner & exhaust, but not sure of the next stages

 

Anything past stage 2 is an exponential drain on the wallet. It gets pretty expensive after cams.....

 

Stage 1 includes slip ons and Air Cleaner Stage I download and possible 2-1-2

Stage II includes complete Exhaust Stage 1 and cam SE 255, 254, 203, 204 Stage II download

Stage III includes cam usually 259E, compression, springs, tuner, Clutch spring, and Stage 1.

Stage IV includes Stage III plus head work, and associated intake and injectors.
There may be cubic inch increases like 96 to 103 or 88 to 95 or 110 to 113 on Stage II thru IV.

 

Thanks, that answers my question

 

Stage 1 Exhaust, air cleaner and retune

Stage II adds cams

Stage III adds heads

Stage IV the works

But nothing is written in stone??

 

Holly Moses...I went from a Stage I to a stage IV...all at once....and with no problems.
Lucky I guess... :-) Bike runs great !!!!

 

I went from stock 96 to stage VI 103 thats computer thundermax ecu and all performance part all the way to exhaust. fuel milage dropped 5 mile to gallon I like the way she runs.
And it only money spend it or have your kids fight over the dollar.

 

There is no black and white definition of what each stage involves, the simplest thing is to think of each one involving bigger changes inside the engine and greater expense. There is no 'stage' for replacing the entire engine, although that is one option if you have deep pockets!