idk if anyone has already posted about this or not im new and donet feel like scrolling through tons of pages but im looking into buying this head unit for my 3 but would like to know if anyone has one and what they think and if i can hook a sub up to it

 

you can hook a sub to anything, just may need a crossover if there's not a seperate output on the head unit. what head unit are you looking to get?
and you can search for how to keep the clock with an aftermarket stereo - may assist your install.