Well some places will not put the things you bring them if not purchased at the shop,and may charge you more, and will not warranty it since you have chosen not to use the items they have and will warranty.Its not really that hard to do, and its mainly time consuming to do a fresh install with supply and wiring, but well worth it in the end, and you can take back out if you decide to sell the vehicle, and utilize for your next vehicle, as everything is become so expensive.You may even ask/ or go to a shop, and just tell them to run the wires, and you can wire the amps up ect your self?I have done that before for a pain in the cahonna 87 300z