I can recommend Galden drivers. Midbass and midrange drivers fit the original locations.
I don't know what the prices are in the USA though.
But i do know that DHL is not shipping these things anymore to the US due to the tariffs. That was announced a few days ago by DHL in Germany.
Not the speakers cut out, but the amp does.
Did the shop or you use an integration device like an idatalink a2b, pac-audio or m0bridge?
If not, did you use high-level in? If high-level in, did you use load resistors or did you disable the speaker detection?
To be honest.... i don't even know where to start to explain what you did wrong...
The front midrange is not getting a fullrange signal at all. It's a highpassed signal without any real bass.
2nd, by splicing into the front speaker outputs after the shaker amplifier you probably triggered the...
Then just get the idatalink harness for that system and have it modified (or modify it yourself).
With slight modifications you can attach any DSP or DSP amplifier to that harness, no DSR1 needed.