I think they both use relabeled Audiotec/Fisher Helix DSP/AMPs
In the case of bimmertech its the Helix 86dsp
and in the case of bavsound its the Helix BMW7.
86dsp has one more channel which means you could
go active on the front doors.
BMW7 has more power especially for the under seats.
I think they both give you a tune and some sort of mounting hardware.
To get more out of it you will need new speakers or the Front doors
and floors. The biggest problem I have with bavsound is they don't list
the power rating on there speaker or at least this use to be true.
You might want to get quote from Unexpected Creations for the same stuff.
https://unexpectedcreations.com/mobile-audio/
talk to Don. (aka 6spdcoupe)
https://www.audiotec-fischer.de/en/m...ifiers/up-7bmw
https://www.audiotec-fischer.de/en/m...fiers/pp-86dsp
The helix match speaker set for the fronts is a more reasonably priced set
for the fronts. Than offered by bavsound or bimmertech I believe.