Just Bought a 2005 GTP

I just bought a GTP, wanted a GXP but the 2005's are a little tough to find right now and I needed the Employee Discount. I love the GTP though. I wanted to know if there is anything that I might expect to go wrong with it (every model has it's quirks), what to look for? Also curious as to what is out there as far as places to look for mods. Not looking for additional HP just yet, just some things to make it look a little more unique (exterior). Thanks