Hey mate, I turbo'd mine about 7 months ago and have never looked back really, now mine doesn't really start spooling until about 1750rpm but when going slow 1st and 2nd are geared low enough for this.
I'm running the TD27 exhaust manifold which isn't exactly the most free flowing but easy to fit up just had to change over some of the exhaust head studs which also supplied when I bought the turbo and manifold.
It's running a hitachi HT12-1 turbo, I'm pretty sure these were off the td27 in the terrano, in hind sight i should have rebuilt it as it seems to be leaking a little bit of oil from the compressor housing which is a sign of a worn oil seal/ring.
my qd32 had 253,000 k's on it when I slapped the turbo on and it seems fine, has a fair bit of blow by but not sure if it's normal for a qd32 or just from the amount of k's on the thing.
A boost gauge and EGT gauge is a must to ensure you don't end up cooking your engine, but also a compression test or even better a leak down test would be a worthy investment as any small issues that may be hidden will surface when being pushed.
I'm still working out the air filter side and for now just running the standard air filter on it's side but it is sucking air from the front of the engine bay which gets hot so not ideal. Looking to see if a ZD30 airbox will bolt into place and then fitting a snorkel as they seem cheap enought.
Also running a xforce 3 inch turbo back exhaust with one muffler and no cat, the bend from the dump pipe to the joining pipe needed to have a few small angles cut out of it and then welded back up to get the correct angle to the joining pipe which wasn't to hard and had to make up a mid bracket as mine was stuffed, it's a little stiff and the flange sometimes vibrates on the floor pan shield but only at load on a hill at 1800rpm.
Any other questions just ask, a few other guys have successfully turbo'd there qd32's as well with good results, you wont look back and regret it, just ensure your engine is up to the task.
