You don't have to be upside down to benefit from AGM batteries.Why absorbed glass mat (AGM) are you planning to be upside down. Just get the cheapest Lead-Acid with matching CCAs to your old batt. 3-5 years is all you'll get at any price today. Read about my 17 year old Optima Red batt still starting my Jeep. But that tech, is over new red tops last 4-5 years. I paid $160.00 New red top $225.00 not the same owners.