Custom tune makes you go vroom, a canned tune might go click, click boom.
Spend the money, go to Brian, get it done right to avoid issues.
Let me tell you why, because there might be an underlying issue with the car you are not aware of. Car is running fine, no codes, ect but the problem could be there. You toss a canned tune on there without finding that issue that would show during a dyno pull/log and bad things will happen.
How do I know this? When I first got my Trans Am I thought about just throwing a mail order tune on the car for my basic mods. Before I did that I took it to Brian for some base pulls during a dyno day, turns out there was an issue.
My "stock" car had been "tuned" by someone and the car was deadly lean, no codes, ran fine, but a mail order tune would have blown that bitch up.
TL;DR, Spend the money to do something right the first time, rather then doubling up costs later.