I figure I'm not really doing that much to earn my free battery tray and installation - just the added inconvenience of dropping in my Jeep on two days instead of just one, and having to wait three weeks for my installation, instead of getting it same day.
And its pretty easy dropping the Jeep off, since they're open 'til 9pm on Thursday evenings, and they drop me off and pick me up from the train station. I've found the guys out at Piranha extremely helpful, and Allan most certainly isn't shy about imparting as much of his knowledge about 4wd accessories as possible