The beauty of the Optima design is the fact that it is a dry cell. you can mount it upside down and don't have to worry about any fluids leaking or gasses escaping. You can actually shoot a hole in one and it will still work.

 

A dry battery and a gel battery are not the same.

An Optima Yellow Top and a Blue Top are the same internal design. The latter can handle deep discharging unlike the Red Top. Deep discharging usually occurs with accessories or sitting for long periods. RT is cheaper than the YT for the same size.

I have the Red Top (BCI 25) in my H3 which required a slight mod to the puck, no mod to the battery box base, and (if you use) a mod to the lid. My officemate has the Yellow Top (BCI D34/78) which required slight cutting to the base and the lid.