For the tuner id definitely go with superchips flashpaq. run around 350$. good investment. I first bought the diablo trinity (600$) and ended up going with the flashpaq. Noticed a huge difference (In performance)
Intake- if your on a budget you could go with a K&N setup. Definitely also look into a Poweraid throttle body spacer. it gives it a nice whistle sound when your getting on the gas. Also completes the CAI system and give you full potential gain from that.
exhaust- if your looking to cut off your cats i assume you wanna be loud. Leave your cats and replace your muffler with a piece of pipe. Sounds wonderful with the CAI.
If you NEED a muffler the flowmaster 40's would sound nice. but id suggest the free flow muffler.
Heres how my exhaust sounds.