Depends on what you are aiming for Scott ó that is what size tyres you want to end up at, what you're doing with your truck or what 'look' you are after.
Yes the kits can be used with the winter packs which normally means the truck body is already lifted by 2".
Theoretically every 1" you raise the body should allow you to fit a tyre 2" bigger in diameter ó the standard tyre for the standard Mitsi truck is 31" so you should be able to fit now a 35" tyre although it will probably rub the arches on axle twisters.
The other thing to bear in mind is that new tyre sizes are measured on the tread while remoulds are measured on the carcass which means a 35" Simex Trekker is 35" diameter while a 35" Fedima Sorocco (same tread pattern type) ends up at around 37"
Based on the fact that the higher the lift the better the truck looks I'd go for the 4.5" lift kit

But that apart ó the
Xpajun lift kits are available up to 115mm (4.5") for the Mk2 (90mm for the Mk1) ó the height you choose might well depend on the amount of extra work you are prepared to, or can, do:
The 2" lift kit is the easiest to fit just needing the removal of the radiator cowling and the inserting of the spacers and new bolts.
Above 2" the following applies:
You will either have to 'drop' the radiator or fit a electric fan
The following hoses will have to be lengthened:
Heater matrix hoses
Fuel tank filler hose
PAS cooling pipe to steering box hose
top hose on radiator if not dropped
The hose to the clutch slave cylinder is border line and may have to be lengthened as is the hose for the brake servo
The earthing bond to the chassis may possibly have to be lengthened or a new bonding point sourced as well
The metal brake lines feeding between the body and the chassis usually are coiled and will adjust to the extra height with no problem
The rear brake hose should run between the axle and chassis
The rear brake cables may have to be lengthened on the 90/115mm kits, using LWB cables on the SWB is a get around
The fuel line pipes from and to the tank are sometimes bolted to the body near the tank this would have to be undone - the tank should be bolted to the chassis
You will also have to raise the bumpers with all the kits as well
Fitting of the 90/115mm kits also allow you to raise the fuel tank (may well be able to with the 3" kit on a winter pack as well)
Quick summary:
With a winter pack (2") and a 2"
Xpajun lift kit you should be able to fit and use a 37" max tyre with little extra work
If you want a truck that looks imposing go for the 4.5" kit