I put up with my HZJ 105 cruiser for about 5 years and it was just tolerable on the highway, load it up with family and camping gear on the roof rack and it was painful, then I bough a camper van and hung it off the back and just became ridiculously slow, not so much on steep hills it always was slow ,but moderate hills saw it regularly back to 60 with a big line of traffic behind me, (i'd move over as soon as i was able) it could just get to 100 on level ground and the only thing I can recall overtaking EVER, with the van on, was a backhoe!,
The cruiser had a bit of stuff in it and it was everything I wanted in 4by but it just didn't have enough power
I was also anti turbo the 1 HZ and issues with the hilux-ish gearbox was also present in my mind, but I HAD to do something, I was pointed to a reputable turbo fitter in the eastern suburbs of Brisbane and decided the part with the $6K, This fitter also goes thru and check all aspects of tuning, not just give more fuel and a heap of boost, checks radiator and viscous fan, he also fits a low water alarm as standard.
He advised me that a 2.5 inch exhaust would be enough but a 3 inch exhaust would help the turbo spool up at bottom end revs, no real gain with overall power, just helps get there sooner.
Mine is set at 10 psi boost, peak torque is around 1900-2000 rpm.
THE NEGATIVE, it does use more fuel when towing, may be 2-3 liters/100ks more, but a massive difference in towing capability,
You have to really watch the temp gauge, full power such as a mountain climb for extended periods can see the gauge climb, it will stay normal for some time, but once it begins to move it moves quick, same can be said for cooling as soon as the foot comes off, the gauge drops just as quick, MUST KEEP an eye on temps, never ever had a problem with temps pre turbo, but I never ever saw the fast lane uphill either, mind you, any 18 year chick in mums hyundai will still leave you behind at the lights from a standstill with out too much problem, how ever once you get going it moves along alright.
The 3 inch exhaust is a tight fit, sometimes under full power in say second gear, the exhaust just touches the chassis somewhere and give just a slight rattle, not intrusive or annoying, it can be heard, no big deal for me.
I found my fuel economy didn't really change much during the day to day work/school/shopping runs, usually get mid to high 12's/100k,
My installer advertised 50% increase in power, well he got 85% out of mine(dyno charts to show0, mainly due to the fact he knew how to tune a 1HZ, valve timing and clearances where done as well as fuel timing and mixtures, injector nozzles where also replaced.
I got mine done at 150000,, now has 210000 and I haven't been back, why?, because he done it right the first time.
Would I do it again? YEP, after 5 years without a turbo, getting it done was like getting a new vehicle, I'm much happier with the cruiser I've got, still doesn't match any 3 liter 4 cylinder brigade of today in power or fuel efficiency, but can get along at an acceptable pace even when towing, I have no plans for an update but i'm not completely oblivious to the current crop of vehicles, I drove my fathers 550nm Navara and was very impressed with its awesome (almost addictive) power but I didn't like the auto, didn't like the transfer controls either, (standard on pretty much all 4 by's today), or the way it handled on dirt roads, a lot of new stuff cant have tyre and suspension mods without upsetting some vehicle computer control module.
Breaking gearboxs, cracking heads, cooking motors, all sound a bit like over fueling of perhaps maybe getting a bit greedy with power and pushing things too hard, all this stuff can also happen to un modified vehicles also, I broke the front diff in mine but so have plenty others without a turbo
I'm glad I did mine and apart from having to watch the temperature when towing up long hills, have had zero problems.
Shane