I would do a mail order tune if I were you, they can be had for 150 bucks, from what I have read on mild cars (like yours) the mail order tune can be very close to a dynotune. Put it like this, you aren’t leaving to much on the table. I went with wait4meperformance.com the guy used to work diagnostics for gm so he knows his shit, there are other vendors on ls1tech that can do the same and save you money