JBL B380 Subwoofer

I just purchased a JBL subwoofer model B380. It is a passive unit with a 15" 2235 driver. I need to buy an amp for it. I'm looking for some advice as to how much power I need to make this thing really rumble. Also, what should I look for in a good sub amp.
Any help would be appreciated.
I had a B380 for a number of years and powered it with an Adcom GFA555 most of the time or a Classe Dr8 with good results with either amp. I found the B380 will not plumb the nether regions however. The lowest response I could get in my room using the BX63 crossover was 25hz. So if you are trying to go way down low you may be disappointed. The B380 came with a particle board slab to rest on but I got the best results spiking it with some short 1 1/2 diameter spikes to rest it on. It does fill in nicely if you are using speakers short on heft into the 30hz range.
Buy a used Bryston 3B on E-bay for around $500 to $800 and you'll be a VERY happy camper. I've owned a B380 for 18 years now and LOVE it. The Bryston 3B has a "bridge" switch on the back that allows you to use it as a Mono amp putting out 400 Watts RMS with REAL current capability. Ask anyone who's familiar with Bryston about the quality of the bottom end of their amps. ( I used the 3B for the last 18 years and just upgraded to the Bryston 4B-ST in bridged mode: 800 Watts into the B380. Now THAT's bass!!