I concur that once you roll daily on baller tires, it'd be near impossible to go back to mediocracy. I'd probably start bleeding internally if I had to go to something like FK452's. (the 452s are actually quite good tires though).
The RC-T4's are a little bit boring, and they don't have an aggressive look to them, they're a little too 'flat' for me. Actually, since you're already rockin the nt-o3's, you should go for an 18" version in gunmetal/hyper black with an aggressive offset. The NT-o3's with a lip looks mad hot.