Best penetrating oil I've ever found (and cheapest too) is a mixture of acetone and Dexron / Mercon ATF. Mix 1/3 ATF with 2/3 rds Acetone and put in a sprttzer bottle. Eats rust and loosens stuck bolts. I keep a spritz bottle handy all the time.
Unless yo are crack home wrench, I'd take it to a shop to have it done. The turbo / manifold assembly has to come off, new gasket put on and everything buttoned up again, not for the home shop really unless you have the tools and a means to remove the parts safely.
You ca run it that way, no issue but like was stated above, soak the studs and nuts down (all of them, nit just that one more tan once before you get home. That will allow the removal without snapping a stud off which is a royal PITA and time consuming to extract. Most times they break off flush and have to be drilled out with a die reclaim bit... (solid tungsten carbide). Don't think you have one of those. Soaking them with penetrating oil will facilitate removal and save you a bundle in the end.