I've looked everywhere and everyone says something different I have an 06 h3 leveled my question is will 35x12.50 20 fit without a lift kit and do I need wheel spacers.

 

This is real easy. 35s fit without any modifications. Wheels make no difference to the size of your tire. A 35" dia. tire is 35" whether it is on a 15" rim or a 24" rim.

If you intend to go hoopty 20s, then do your research on the wheels you are looking at. Plenty of wheel size threads, note H3s are hub centric, buy the right wheels, no spacers needed.

 

When you say they are hub centric does that mean a 0 offset. So don't get a positive or a negative offset?

 

First on the simple Google search: Hub Centric Vs. Lug Centric | Greg Smith Equipment Sales, Inc.

 

The center hub of a H3 is 100mm diameter.
That means ANY aftermarket wheel's centerbore must be 101mm diameter, or larger.