3/32' v 1/8' ?

The components are compatable, but whether or not your chainline will be straight is another matter. It probably won't be out by much. Search for "transmission database" thread for user-recommended combinations.

yeah, that is another concern, the chain tension... supposedly, if i put the shimano freewheel with more tooths, I will need a new chain, since my current one is already at the max tension (i think).

I will search that transmission database, thanks! :)

3/32" is narrower than 1/8", so you can use 3/32 cogs or chainring with a 1/8 chain, but not the other way round

and what the hell is a nood?

Ok, if you tell me it's safe I believe it is :)

nood = noob, but nevermind that... i meant i'm a noob when it comes to single speed bikes...