Well seeing as a stock RB26 makes more power and torque than a TB42 I can't see how it could be any worse than the hunk of junk TB42 that is in it now. I know that turbo's take time to spool up, the RB26 WILL be staying TWIN turbo, they are quite responsive as it is. I have been around Jap import motors for some time now and know that they are tuneable to just about any job. The workshop who are going to build the motor have more experience with this motor than just about anyone else in the state if not the country, so I'm 100% confident in them to be able to come up with a solution for me. Cams and Cam gears are amazing things and there are so many different Cams available for the RB26 it isn't funny. I will probably be stroking the RB26 out to a 2.8 or so, I'll have to talk to White Hot about these little bits closer to the time when I'm looking for my Half cut. I'm going to get the Patrol Dyno'd at White Hot soon to see where the TB42 sits on the chart and to set a Ramp rate on their dyno that resembles how heavy the patrol is so when it comes time to tune the RB26 we will know a good ramp rate so I don't blow it up when I finally get it on the road. I will be using a good ECU with either two maps or get a happy medium tune with high boost for when it's just the patrol and a lower boost setting for when it's towing to save running a massive fuel system to cope with the extra load on the motor while towing.
I have seen a 4 Runner with a 2JZ rock crawling, mudding and just being an all rounder. I have also seen another 4 Runner with a 1JZ doing the same, these motors have pretty similar power/torque figures to the RB26 and I do realize that the 4 Runner probably doesn't weigh as much, but I have the low ratio gears that have brought the ratios below that of a stock GQ with stock tyre size.
As for budget... Well how long is a piece of rope? I don't set budgets when modifying a vehicle, it's never finished.