The ESP Guitar Company

I couldn't find much here on the piezo ltd, can anyone tell me if some easy upgrades, or if the hardware needs upgrade? I'm thinking of switch the nut to a graph tech black tusq, schaller s locks, and some black nickel covers for the jb/59 combo. I know it has a good bridge, being tone pros. I find that it comes out of tune when I play it for 30 minutes plus. Any ideas, or if anyone has experience with this guitar, I'd love your thoughts. I'm new to the forum, and this is the first 1k dollar guitar. Thanks!