Instead of following Kweasel`s advice you should start on a junk engine for practise and determining the right tools, that`s what I did many years ago. I started on a worn out TRX .15 engine from an rc-car and then some more or less junk aero engines.
If you have a steady hand, the right tools and feel up to the task, then just do it (be moderate and think before you cut) and you will enjoy more power from your engine than your buddy get from his
If you know this is over your head THEN follow Kweasel`s advice and just enjoy them as they come from the factory, but then you will not learn much about engines.

Do some research on the web before you go, there`s alot of info out there, especially in the different car /engine forums.

Typo:-)