I'd bug the installer...

I've got 2 really cheapo (less than US$100) Pyramid amps, one 4ch
running stock front components (VW Polo '01) and 8" 3ways at the rear
and a 2ch running a 12" sub. No clicks or pops at all.

I'd look at how the amp is supplied with power, how/where it is
grounded and how the signal cables are routed...

/Michael

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/Michael