Best two amps to bridge for subwoofers.

Can anyone help? I'm looking for two reasonably priced amps ($300-$500) each that I can bridge to run my two Citation 7.4 THX Subs. Looking at Adcom 555 II. Already using Carver 500xTHX. Should I buy another and use them in a bridged mode? Can these subs handle that kind of power? Thank you for your help!!!!
i'm currently using a pair of bridged adcom gfa-555's - the earliest usa-mfr'd versions, w/the smooth faceplates & rack handles. they're driving a pair of the larger vmps subs. they do an excellent job. i can't imagine anything doing better at anywhere near the price. i tink you'd have to spend upwards of $3k for a pair of amps before you would notice any improvement, and then it mite still be marginal at best.
Thank you for the valuable information.