Hi!, Welcome.
First off, dont listen to half the assholes around here. You cant expect must of the guys that have heard it all! As long as you are just looking to get a little bit more out of you shee and not trying to go 100 here are a quick list of what I know
Vito's Super stock pistons (you cant port your cylinders at all with this) 8hp
+4 timing 2.5ish hp across the curve
Welded crank 0
Mods to improve performance:
Porting
Larger carps
Different pipes
Aftermarket cylinders
These are just a few of the performance mods that a lot of the guys here make. #1 is porting, rejetting and getting your crank welded. Higher hp causes the crank to separate which is bad!
If you have questions about who what where when use the search function and you will find the answers you are looking for. Welcome to the site again and hope you find what you need.
Take everything with a grain of salt and understand that the banshee brotherhood starts with a "fuck you" and ends with "we will always be here to help."
Adam