i did the math...i need a USA-400 or 600 if i wanna run just 1 amp to do my 4 doors and dash cause its 1 ohm stable..i would have a 1.34 ohm load...if i run 2 amps..1 for my dash and another for my doors..then i would need a USA-200 or 200X cause its a 2 ohm load...but 200X has more power so that would be better..and for the dash a USA-50...its a 4 ohm load...amp is 2 ohm stable..25w rms to each dash speaker..so its all cool..oh well...just save me alot of time just to find a US Amp 4 channel...if you know anyone that has an old school 4 channel let me know..just PM me..thanks