08 RZR 800 Standard lift & questions

Hello everyone new to the forums but have been looking around for awhile now. I have an 08 800 standard, have a set of skinny wide 31 inch outlaws that i want to put on it.

1. Would it be a good idea to convert it to the "S" model? Not exactly sure if this is needed or what it does all together and say for instance if i change to a 5-6 inch kit later would the "S" be a waste?

2. Would just a 3" lift fit the 31’s. Seen that on the S model with just a 3” lift people are able to fit 30’s. Or a 3" lift and forward a-arms. But would that be to much for the stock axles? Seen a couple people on with a similar setup but dont specific whether they have stock axles or not.

Thanks for help guys , have learned alot through this site already.