Yup that is a solid game plan. You will feel a big improvement. Like IndeedSS said, Overkill's PCMs are not canned. He customizes it for your mods. You are getting the benefit of a guy who has LOTS of experience tuning these cars. He also has a lot more resources at his disposal. Like he says that he has worked with a tranny shop to get the line pressure set to be best for the tranny. Not something the casual tuner can do. I've have been very impressed with the tune I have. He can nail them down very well. He has a generous retune policy too. Retunes within 30 days only cost you shipping. You can send him scans and he can make changes if they are needed. Not everyone has the time or money for a tuner (and laptop if you don't have one). To learn how to tune is going to take hours and hours and you'll be burning a lot of gas too. I learned from my experience tuning carburetors that I much rather have someone else mess with that!
On the intake, I've got a Wizaired. It is a nice setup and I like it, but really there are cheaper alternatives. If you are on a budget I'd try something else and use that money for other go fast goodies.