you can always put some JL 300/4 if you got the cash...if not...a nice US Acoustics (USX 4065/4085) amp will do.
If you REALLY WANT a HIGH END AMP for VERY LOW PRICE...there is this guy that sells NAKAMICHI PA2004 (100 x 4 @ 4ohms) for $350. SHipped!
go to
www.caraudioforum.com
Mike