I had spent the money for a red top and ended up with a dead cell after 18 months. Fortunately, the warranty is excellent and it was replaced. I believe they have a 36 month full replacement. The balance of the 36 months is honored with the replacement. The reason I like the gel batteries is because where they are installed on the C3's. Being inside the car, there is the possibility of gas and acid fume accumulation when it is frequently charged. My experience is that this doesn't seem to be a problem with the gel types vice the liquid electrolyte ones. Also, you don't have to worry about spilling any acid on your interior when manipulating them in and out. The one thing for sure is that you need to drive the car regularly to maintain the battery in good condition or use a float charger (battery tender) or yours will end up like mine did. I will try to remember to go look at mine and let you know which size I have. I would think the '81 and '82 would take the same one.
