A vid popped into my feed that shows the RAG method of plumbing in the oil return (RAG = rough as guts) - cued for convenience (it's a 3L but the principle is the same):
Your choice on how you go. The fan on my ute has the oil sump fitting welded - I prefer a good job over a quick job.
Also note their experience with the clutch (bearing in mind that their vehicle has ~450,000 km on it). A note of caution there. My ute blew its clutch about 80,000 km or so before I did the turbo. I replaced the OEM with an HD organic with a claimed rating of 480 Nm of torque. So, I had no qualms about putting a blower on the 5L. You will read commentary out there about the G52 box that runs in an LN167 in terms of its strength / durability (they also talk about it in the vid). The reviews are mixed, however there is significant commentary that I've tapped into that as long as the turbo job isn't boosted to the max and AFRs are sensible, then what I've got should last with appropriate care. I'm not about to go hard core rock crawling, so I think it's a case of treating matters to suit how you'll use your vehicle.
What you've got in terms of your driveline is one to think about. Your comments sound like you're not planning to go nutz, so you can't go too far wrong with good sense behind you.
Regarding boost pressure, that's tech detail that I can't speak to with confidence. With my deal, I went for an HD Auto kit including a Garrett turbo (GBC17-250 36mm) that's set up with out of the box standard actuator set at a nominal 0.5 bar (7.3 psi) and had the job done by the kit supplier. The setup's final dyno tune reported a pretty flat 15 psi manifold pressure and an AFR of 22 down low and then flattening out to 20-21 across the mid to upper rev range.
By blow off valve, do you mean waste gate? Excuse my ignorance but doesn't the waste gate, simply bypass boost across to the exhaust? For the Garrett that I've got, the waste gate is integral to the whole unit so no plumbing required. If I've got the wrong end of the stick, forgive me. I'm not a turbo guru by any stretch. Your turbo sounds like its similar to Toyota unit used in the newhilux.net post that I linked to above. From a quick search of the first page, I'm not seeing reference to either waste gate or blow off discussion.
From my research, there's good value in planning in a dyno tune so that you can make sure that the fuel delivery is sweet. The last thing you'd want to do is run the engine rich and give yourself engine temperature problems. Hopefully, that's part of your thinking as well. Sounds like you're wanting to minimise outlay but even so, that's another thing to consider.
