I have a 88 sammi with 33s. I am looking at buying a 6.5:1 t-case and 4.57 RP gears just looking for some input on the combo. Do i need to gear both T-case and RP.

I had the 6.5.1 t case gears in my 87 sami with 33's and stock 3:73 axle gearing and it did just as good as stock on the road. A buddy of mine has the same set up except with yota axles which are 4:10's and his does a little better on the freeway.

6.5.1's with the 33's is all you need in my opinion

You should be fine.  My cousin is running the 8:1, which has the same high range gear set as the 6.5:1 kits, with 33" Swampers.  The tires are a little heavy, so he doesn't run freeway speeds very well but plenty of power for normal driving.  A lighter set of tires, such as Pro Comp or BFG's, are probably a better choice if you plan on spending a decent amount of time on the street. 

6.5:1's are in theory, supposed to set a stock zuk (3.73R&p) with 33" tires back to stock...

A 33" tire does have quite a bit more rotational mass than the sock 205's, so you will be wee bit slower.

You should be fine with just T-case gearing, but lot's of people do gear the axles down also.  It all depends on how much money your willing to spend.

Amilla

Oh yea, don't forget to upgrade your t-case bushings.  And if you run the stock t-case mount put some extra bracing on the long mount, and use lock tight on all your mounting bolts.  Otherwise you will twist things up then brake your t-case in two. 

or just buy the dang mighty kong.
oh and right now you can get an entire  rebuilt t-case from trail tough for $720
heck of a deal, wish I had more money

www.trailtough.com
6.4:1 Rebuilt Transfer Case           Price $969.00 Sale $719

Refundbale core charge $350.00


COMPLETE REBUILT TRANSFER CASE ON SALE NOW FOR $719.00 (A $250.00 savings !!!)PLUS REFUNDABLE CORE CHARGE $350.00 (must be in rebuildable condition)

How long do you guys think the stock driveline will last with 33's. I dont drive it on the roads and all i do is play in the mud

How long do you guys think the stock driveline will last with 33's. I dont drive it on the roads and all i do is play in the mud

It depends on the U-Joints.  If you go with the Napa brand cheapies you will probably have it go out on a regular basis.  If you use the stock OEM replacements or the Mitsubishi replacements (no idea what ones, but Trail Tough sells them) they won't have any problems holding up.