hi.
why do you want a super charger?
Personally i would use the money on a better modded engine.
But theoreticly when you juse a charger it is not entierly corect to say you wil get more air and therfore run lean..That is a mather of tuning.
The charger wil also force more fuel thru the system if you adjust it corect.

Are you dragracing? or oval running?
If youre not,dont by it!