picking an amp
 

Well all these posts i have been making mentioning my 1000w alpine and how im picking a small sub and all made me think i can downsize my amp and get a couple bucks at the same time. Sooo, im going to trade my amp and now need to know how to pick the right amp
ive decided to go with one sub
10 or 12
250-500w rms
dont have the sub yet

so what factors need to be considered and what questions should i be asking when looking at used equipment? what brand names to be looking for?

i got offered a mrd-m501
is alpine the way to go? any comments?