Is your customer happy with the way the car performs now?

If so, I believe your extra efforts towards assisting in this case speak for themselves. IMO, it is up to your customer to determine if a complaint should be filed. DO recommend to your customer that she not return to that indy, however.

She trusts YOU, remember.

If at all possible, guide your customer to this site, and encourage her to post her own comments if she so desires.

I would avoid "shop vs. shop" bashing at all costs.

Good luck!