Sorocket replacements

Hi. I have a question regarding my sprockets.

My chain and sprockets are about ready to be replaced.
Now on standard chain and sprocket my bike will lift the front wheel in first and second on power alone
And on a dyno has a top speed of 164.7 mph.

What I'm asking is if I add say 2 extra teeth to the back, roughly what type of top end speed would I lose?
Is going up on the rear better than going down on the front?
And how much More initial pull will those extra teeth give me?

Thanks in advance

Cheers Gary