AC compressor Swapped/Now low power/dirty exhaust

[JRC08]

Good Morning members. I've been lurking through the pages attempting to find resolution to this problem and decided i'd sign up and just reach out. First off, I'm about technically inclined enough to get me into serious trouble...so bare with me. Recently bought a 2005 E53 X5 3.0D. Car is very clean, about 240K km's on it. Prior to the purchase the car was VERY snappy (part of the reason we bought it). The previous owner agreed to fix the AC as part of the purchase agreement....mechanics swapped AC compressor....but now, it has very little power. The idle seems clean, starts well (maybe a little bit slower than before, before it was on the second the key turned), but the acceleration is poor and the exhaust seems like there's A LOT of unburnt diesel in it. Part of my inquiry is....i'm thinking injectors but with the recent service, I feel like maybe there is a vacuum issue due to recent service. The other part of the problem is; I live in hungary and the language barrier can be very difficult. I'd love to be able to pinpoint the problem prior to bringing it in to the service place so I can just point and say "correct this". I know some of these symptoms have been addressed before, but I hadn't seen any with clear resolutions. Forgive my ignorance, but I believe the 3 liters are turbocharged? I've looked for schematics to I can attempt to inspect the turbo (because when my wife rev's it, I get ZERO report/noise of the turbo spinning). There are no trouble codes that have popped up to cause any dashboard DTC's yet, and unfortunately i left my SCANTOOL in the states...all help appreciated.

thanks,

Josh-