Not convinced that you're gonna make MBs sound good, but:

1) The JL amp has grainy and harsh highs and exacerbates the MB sound.

2) The PG amps are no longer what they were and I wouldn't recommend them for anything.

3) The kenwoods are meh.

Many 5-channel amps are long enough to challenge where they will go in the X5. If it's between the tray and the removable load floor, you might not be able to fit some 5-channels.

That said, I'd consider the DLS CA51 and RA50, the Audison Srx 5, and the Arc Audio 5150 XXK.

Zapco doesn't have a 5, but they have a 4 and a mono.

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