Guidelines for subs' Amp wattage?

It’s been 15 years since I last installed a car audio system and Amps were rarely called for back in my day. Nonetheless, I am inow installing two 12” Sony Xplod Subs in a Bandpass box I just purchased for my son’s car.

What size (max wattage/ohms) Amplifier should I get to handle & power these subs adequately? Any recommendations?

The car has a Sony XPlod deck 52wx4. The subs are rated as follows:

• Model – XS-L121P5
• 12" Polypropylene Cone
• 1200W max input power (350W RMS)
• cone design
• 4 Ohm Voice Coil

Any advice or "rules of thumb" appreciated

CW - Cols OH

They won't need much in a bandpass enclosure.  I think I can read single 4-ohm voice coil from your post above.  In that case you'll want a 2-ohm stable mono amp.

http://www.cardomain.com/item/USAUSB600D

Here's one possibility.  Something like this should rock those subs and will probably even be a bit much.  My advice is to completely ignore the max input spec.