Originally Posted by Simpler=Better

I'm going to assume that your 617 is like most of the ones out there, and is really only putting out ~90hp. If you have over 100k and never rebuilt the injectors, or checked the chain stretch, or timed the engine you're way below the stock ratings.

Spraying methanol can net you another 20hp or so.

Granted, these are just the numbers that people who have run dynos reported back. Some mods are said to be felt but don't have data, and since I haven't made the mods myself I can't comment on exactly how much power they make