I tracked down the owner of the Delica and it turns out it's someone I already know, he just got the truck a couple months ago and I hadn't seen it...

He loves it but says the engine is a dog, it can barely get up to highway speeds. I haven't had a chance to look at it closely so not sure exactly which engine he has, but I do know it doesn't have a turbo. My guess the engine is a 4d56, same as the quad in the craigslist ad. The seller of that truck did a swap for a456d with turbo and it's claiming a huge improvements, but he's trying to sell it so I guess you have to take that with a grain of salt.

My friend is considering installing a turbo, but I'm wondering if any of the diesel experts here have any thoughts on whether or not that will make a significant difference or not. Does it make sense to add the turbo, or should he be considering something more drastic, like a V6 swap?