Stage I vs Stage III Jetting

[TonyW]

OK, so I've decided to take the plunge and fix my 2000 GS500's 'flat spot.'  Seems to me that, for the price of a new main jet, new needle, and an air filter, I can do a stage three job instead of Stage one.  (I'm not going to change exhaust system {I like being fast but quiet}, and tech support at 'Factory' says new exhaust is not needed for stage 3, but the air filter is).

So my questions are, why wouldn't I want to do stage 3 - why doesn't everyone do stage 3 instead of stage 1?  I'm not a mechanic or mechanical engineer but I suspect that stage 3 = more air and gas burned at all revs = more torque across whole rev range = more HP across whole rev range.  

Can anyone tell me what I'm missing, if anything?

Thanks!

[JamesG]

yes the exhaust.

You have to have a freeer flowing exhaust to make a "stage 3" jetting work.

Otherwise you are pouring more water into a bucket with the same small hole in the bottom.