What amp for alpine type r speakers?

[zako 10+ year member]

I see. The setup with four speakers makes more sense now. I think the amplifier choice depends on your budget. There are 4x100 watt amplifiers that cost over $400 and others that cost less than $200. Buy the best one you can afford, but within reason as there is no point in driving $160 speakers with $600 amplifier unless you intend to upgrade the speakers. Among the budget stuff, if you can fit a boat (or trunk) anchor sized amplifier, then MB Quart ONX4.125 could work nicely, and it costs under $200. If you want an amplifier that small, neat and efficient with better quality internal components and specs consider some of better Class D amplifiers, like Alpine PDX-F4 or Kenwood XR-4S.