Lots of rumbling on @ToomTom and @Niran's garage threads, about people's expectations and experiences with performance workshops.
I feel like it's a conversation worth having, because clearly we all have somewhat different levels of expectation about what we'll get when we take our car to a specialist workshop. And I have some grumpy rants to have about it as well.
Keep it constructive, I guess.
My 2c:
On the one hand, virtually every modified car is different. There will be slight variations from build to build that introduce unique differences that have to be allowed for when you setup/tune the car. On the other hand, these are "experts" and they usually charge like a wounded bull, so the service should be premium.
Because of these variations in cars, things sometimes go wrong, or don't work as well as expected.
So my number one rule for a workshop: communicate. Tell the customer what's going on. And for the love of all things Subaru, have your ducks in a row when you talk to them. Don't give them some wishy washy bullshit with 9 different things that you think it might be. You're professionals, damn it, with a workshop full of fancy diagnostic gear (including, probably, a dyno), so come and tell me what the issue is.
Rule number two: Unless the customer is like "I'm coming to get the car", don't push it out the workshop door if it's running like a bag of balls. Generally people spend like 6 months or more building the car, a couple more days for you to iron out some little issues is nothing; the customer might be a little bit disappointed but if you follow rule #1 and have a concrete conversation about why you need the car longer they will be understanding. If you hang on to the car but fail at #1 you look incompetent. And so help me, if you have more than one car with the same issue, and you fix it on one car and don't fix it on the other, and then tell the owner of the second car that it's the same issue as another car that you already knew about but you didn't fix it on their car, you look incompetent.
I've taken a car to get tuned, it had issues, the tuner nailed it down to a single factor, laid out my options, we made a decision on it, got it sorted. Easy.
Seriously, I feel like I have had some sort of blessed experience with tuning. Drive/trailer the car in, leave it for a couple of days, drive it out.