Changing minor things and tinkering is way different from going from stock 87 to premium performance. The computer needs time to learn how to drive, so if you get the tune, go out and floor it everywhere, then drive like a grandma the next day, the shift points will be messed up. I used to drive like a bat outta hell everywhere I went, then gas prices hit $2, and I slowed down and now easily get 400+ miles to a tank.
Go disconnect the battery until you leave work, then drive home like normal, not racing it, and not babying it.