I received my timevalve y-pipe for my 1994 E500 and had it installed today. Here are my thoughts:

It is well built, but mine had lots of little bumps bumps from overspray during welding on it. Only cosmetic, but wish it wasn't there.

Fit was also difficult. It eventually went on well, but I had to jimmy a crowbar between the two pipes that go to the cat so that everything lined up.

Other notes are that you might want to buy new gaskets as they are almost impossible to retrive out of the old resonator.

Now for the good part...this thing works. Exhaust sound at idle seems the same and on acceleration is a little deeper, but the HUGE difference is in throttle response. I can't speculate on hp gains or 0-60 times, but the car is quicker and more responsive. Period, end of story. Wish I had purchased one sooner.