I'm a longtime audiophile, but I know next to nothing about car audio. I'm hoping to get some suggestions for good mono amps to look out for on the used market between 150-350W @4 ohms that are likely to sell for around $50 or less. I can stretch to $100 if the extra expenditure gets me something much better sounding.
I'm going to be driving an Alpine SBR-S8-4 Type-R Loaded Enclosure. I don't care about huge window-rattling SPL, I care about quality and accuracy at medium volumes.
I'm having a lot of difficulty finding the kind of reviews and information I'm used to working with when I'm researching components for my home system; there, if I see some old Nelson Pass design I've never heard of (for example), I don't need to look for detailed impressions, I can be confident I'll be happy with it. I don't have anywhere near that level of comfort with car gear.