cosco no longer sells them, if u can find a yellow top for less the $200 buy it. the cost of lead sky rocketed...red top are over $200 at Walmart. i do not know about the other brands...but they could be good batteries as well.

interstate
 

i got my yellow top optima from interstate for 173 $ including tax

Spiral cell. Yes, that's correct. I just couldn't remember it at the time I posted.

That and the Orbital Extreme Duty are the same batteries according to what I was told.

I have pretty much exactly the same set up as you with the 605 amp and a speaker amp and what i found is the same as you with the bass topping out at about 23-24 but any louder than that things begin to distort at a very small level that is hard to hear but over time it screwed my speakers. So if you want your bass to top our at 35 your probably gonna need hearing aids at a very young age cause that may give some nice bass but the highs are just destroying your ears. As for the yellow top battery i was told that it is cheaper to get a deep cycle marine battery which costco does sell and it is a lot cheaper.

well i got a red top instead... i figure it should still do me well... i dont think i will be needing anything bigger... should be running a 2000 w rms mono block and a speaker amp
i figure throw in say a 5 farad cap and i should be set
but in the mean time... the battery is great compared to the old crappy one.. and its smaller too hahah....
cranks real good... and well ya nuff said right?... i got it for 160 w/o tax... so i figure that was a good price

where from?

that place of buy sell... i got the last one... but thye said in 1-2 weeks they will have more... and should be selling them for 170... which is still a good deal