I would like to replace my stock HU with something like an Alpine CDA-9857 or CDA-9856 with iPod controller. I plan to use the same factory amp and subwoofer but replace the door speaks and probably the tweeters too.

I would like to keep the use of the audio controls on the steering wheel if possible. Is it possible?

TIA

No problem. Use one of these PAC steering wheel control adapters (http://www.pac-audio.com/products/productsCatagory.asp?mmSearch=Steering%20Wheel%20I nterface).