beat you cant wait till you get it all put on and custom tuned. 300rwkw with the mods you have should be done easy with a good tuner. but in saying that your stock 4speed auto may struggle depending on how you treat the car etc. I ran 272rwkw 15psi for 1 year before the auto went. some last a week some have never had a problem. even people running over 300+rwkw still dont have a issue. 40rwkw is alot of difference aswell mate so 260rwkw compared to 300rwkw is big,I went from 270rwkw to 290rwkw roughly and is a big differnce and I have pretty much same mods as you cooler,injectors,hiflow cat,minus centre muffler. CAI and nearly punchin out 300rwkw with stock valve springs and fuel pump. anyway I think you should go around to a few differnt tuners and go with who you feel happy with and trust. for $700-900 I would just go with Nizpro if you going to spend that kinda money IMO custom tune start around $500 to around 1k. good luck with everything and will be waiting to see the finsh results. Rob