Right. Not that it isnt possible. But like I stated in my post, to build a turbo that cheap.....it will most likely be a small turbo. Given a small turbo, this will drop his gas mileage significantly, which isnt that desirable as this is his daily driver. Yes, it is possible to do a reliable k-swap plus turbo...and possibly tune for under 8k. Its going to take lots of time and luck, the tune probably wont be from a reputable shop unless he knows the owner, and the turbo will be small thus ruining his gas mileage on his daily driver.
My suggestion is that he builds a better turbo kit, with a bigger turbo to allow for better gas mileage, and gets a reliable build on his D17, with a good tune.....for roughly the same price. He will also likely make better power....or at least get a more desirable powerband as his power will be in the upper RPM's. All this being said.....you are right. If he went K, he would have a MUCH better base to roll off of. If you are strictly limited to 8k total.....I say go turbo D. If you will have more to invest later on....I say go reliable K-swap, then save whats extra and wait until you can turbo that with a bigger, better turbo.