I have two 150 RMS Subs, should I buy an amp for it or two more subs? What do you think I should get first?

two ways to go; 1) if you 're done on how many subs you want in the vehicle then buy an amp or 2) buy more subs then add an amp.....my best solution; spks are your first thing you get towards the design of a system,then the radio,equalizer and the one or two amps.....I am old school installer, I use capacitors to change the sound of a speaker not a equalizer....my old system in my '87 dodge extended van had 8 pairs of speakers and one amp that I had got in a garage sale....optimus 340 -4 channel, by the time I got done with twinking it out I had close to 1600 watts at 1 ohm stable and about 137 decibals.....

Well.... If you can't power the 1st 2 subs yet, why are you worring about buying another set. Power what you got first then work on adding to the system later on when you got the cash!

You want to run 4 subs? Are they all the same? I would get one amp for every two subs. So buy the amp now and see if you want two more subs later.

amp first

make sure you have the right size box and it is built well. then a good amp for them...

neither. Nobody else wants to hear it.