The cheapest big tooth kit on the market for a 4x4 is the oppliger kit which is around £1950 for the gear kit, you then have to get that fitted into your casing, if you don't DIY it, it will be a few more hundred quid to get someone to do it for you, if you don't run into any unforseen problems whilst building the box you're looking around £2600 all done, 6 paddle AP clutch is the way to go if you're looking for big pony power but they are a bit shitty, they are either on or off, there's no inbetween

Luciano