+1lol i think most of the guys on this forum will agree with me on this but a tuner is one of the first things you should get. It'll read and clear engine codes, correct your speedo for different gear ratios or tires, let you adjust timing and parameters of the ECU, not to mention give you a few more horses if you change to 93 octane.
A dyno tune in my area will run about $150. The canned tunes are on the conservative side but do work well.
A custom tune on a stock car is not worth it because you will probably be doing more modifications in the future that will need to be compensated with by changing the tune with your tuner. The canned tunes will not hurt your car.