I need MPGs and HPs out of 5.3 2001 Z71 for $1000 at most.Any advice?

Hey guys im new here.I just bought an 01 Silverado with the 5.3. Its not a new truck, has 105000 on it, but it is new for me. Im trying to get the most bang MPG and HP for the buck...I need some good advice.It is bone stock.Im planning on exhaust, and hear alot of you talk about having it tuned.Questions... can i cut cats off without affecting computer? What is best cold air intake? Are hand held tuners out of question?Where in Michigan should i get it tuned? Please remember only have about $1000 to play with, and wife is on my ass about that. Thanks for your time guys.