914 Battery, Odyssey models, other AGM brands? Options

[JamesJ]

Hello World,

I am needing a new battery for my 2.2 four cylinder 914. I have read many of the battery threads from recent years. I know many of you have had success with Optima, but I've also read about the quality concerns in recent years. The Odyssey seems like a good choice as I've not read any threads addressing quality concerns with this brand.
The Odyssey Group 42 standard size battery for our 914s is 600 CCA, is as heavy as a lead acid battery at about 40 lbs., but it is a plug and play(no extra bracket required). I am not opposed to this option, but like the idea of a much lighter battery.
Odyssey sells a PC925(330 CCA at 24 lbs.) and a PC680(170 CCA at 15 lbs).
My mechanic friend recommended that I stay within 100 CCA of the standard size Group 42 battery, which would mean at least 500 CCA.
My car is stored at a remote storage facility that does not have power, so a battery charger/tender is not an option for me. I currently disconnect the negative battery cable when not using the car, but will purchase a disconnect switch when I purchase the new battery. The car is not a daily driver, and it's not unusual for the car to sit for a week or two at a time without starting or driving it. I have a/c and a CLA for my cell phone, but no radio or other electronic gadgets and I don't run any of the above with the key on.
I've read where several of you have the PC680 or PC925 and have not had any starting issues, but I don't know how often you start your cars or if you use a battery charger/tender to keep it from draining down. I live in California, so CCAs are not as critical as other areas in the country.
Any thoughts on CCA ratings or other issues I should consider? For terminals, do you use the SAE battery posts or the M6 receptacles? Other AGM brands recommended?

Thanks!

[technicalninja]

I've used the Optima batteries in quite a few projects.
For vibration resistance, no gassing, and no acid leaks they are hands down the best.

My problem is they haven't lasted over 3 years for me, and their warranty is for 1 only.

They also have to be either charged in parallel with a lead acid battery or charged with a special AGM smart charger.

I will use an AGM battery in my 914s but it will probably be a normal mass-produced battery like the MTX/MTZ line from Interstate.
It helps that I am an Interstate dealer and can get these as cheaply as anyone else.

The MTZ line has the longest warranty from Interstate (48 months free replacement) and I'd expect one to live 6-8 years.

Interstate batteries is an Optima wholesaler, and I can get those at bottom price as well.

I'll still go normal over Optima for a street-based vehicle.