Similar to everyone here... but just like "tonywyso"...
My logic is to go with the highest cranking/deep cycle battery I can fit in the allocated space for an AGM battery. My SPF has the trunk mount battery similarly...
1st choice - Odyssey (could not find the right size with large CCA)
2nd choice - Duracell (CCA was less than the Red Optima)
3rd choice - Optima Red Top .. 34/78 (9004-003) had the highest CCA so installed it in my Cobra.
https://www.optimabatteries.com/products/redtop-34-78
I add Battery Tender leads on all my sports cars and use:
https://www.batterytender.com/Batter...nior-12V-0-75A
All my cars are on the Battery Tender when parked in my garages... longest battery life was 11+yrs old...
Cobra really cranks nice with the higher CCA !!!
Good luck .... let us know what you went with...