Quick question, are these expensive?

Don't think it's a bad price for a full interior
 
These claim to be fully electric and heated. Unless you have these options already on your car these aspects of the seats will not work without a lot of extra work. Heating not a big issue, but you would have to remove all the motors etc and convert the seat back to a manual one and I doubt that is an easy task. You could of course simply use the covers from these seats to replace the covers on your existing seats and then replace the door cards etc. Looks as if the speakers were Bose so if they are still in the door cards you'll need to swap those with your current speakers (unless they are Bose as well)