I am considering replacing the factory amp. Will I loose any functionality (bluetooth, steering wheel controls, xm) by doing so?

I asked an installer about leaving the factory amp for the center (Is the center needed for bluetooth?) and having a JL 300/4 installed for the fronts and rears. They said it depended on the outputs of the head unit. What kind of outputs does the head unit have and how many?

I already have replaced all the speakers with Infinity kaapas and I have a 10 in JL sub and and amp (250/1) already installed.

Would it be better to get a 5 channel amp and just get rid of the stock amp?

 

removing the factory amp will run you into a bunch of problems, the HU output is to low and a line driver will be needed. YOur JL amp should high level inputs so all you have to do is get the signal after the factory amp and lead it to the JL amp. I would leave the center speaker alone because unless you have an 07 TL or you listen to DVD-A all the time, the center is inactive and its not worth spending money. I would upgrade the Sub and speakers together so it sounds good and the lows don't lack. This is my opinion on the subject.