Hey guys just wondering what ipod adaptor you guys would recommend for use with an iphone 4?

And secondly my car didnt come with the factory amp and after listening to my friends r32 that has one I think I could settle for the sound of that. So I'm wondering should I just get something plug and play like the oem amp? Or should I just find a 4 channel amp and use line level inputs?

Also is the factory amp 10 channel or just 4?

I'd just get another head unit but I have the extra stacker in the armrest and I dont really want to render that useless.