High speed gears?

[boosted 230]

I had a question about installing some 6:1 gears in a 94 gas club car... im leaving the cart stock height and on stock size wheels. My friend and i have worked in a golf cart shop for several years. We have done just about everything you could imagine to a cart, including many high speed gears in electric club carts but never in any gas carts. For those who have done it, i was wondering if there are any special tools needed or if i will need to have any bearings pressed in or out? Also, about how hard is it on a scale from 1-10? thanks.....