€2.500 yikes! For a mild steel system that will eventually fail and sounds bad, that is disappointing indeed.
You may want to check with the good people at Van Dijk in Lisserbroek. I got a slightly used stainless system from them (likely for under €500 but don't recall now) in 2003 and have been 100% happy with it. Clamped it together, still looks new and sounds great 20 years later. Not tinny or raspy sounding at all.
Unless your MB system was welded together, you can offer it on Ebay/Marktplaats, some people really only want OEM on their car, and recoup some of the cost. Even if it has been welded, you can have it modified to clamp-style, or just cut clean through to make it 'shippable' and have next owner weld back together.