Well I already bought the 8500's. They handle 600 RMS compared to the 400 RMS on the 7500's. I also bought a stinger battery for the cap. I am waiting on a box though because I need a different box for the 8500's. The box is free of charge though. Only thing I am paying for is the price difference between the subs. Oh yeah, and the battery. I may also purchase an additional amp, all depends on my decibel level. I just want to be over a 141.1, which is what I had with the 7500's. The shop is giving me a month with the 8500's to determine if I want to go to the 9500s. In six days I will get to ride with the new system. Oh yeah and I got another touch screen head unit.