battery size

Is the one that can fit the battery tray perfectly and can put out the most CCA's

my check engine light is on and code says that its my fuel managment system. My mechanic says its probably because I need a new battery. My stereo makes the dash lights pulse with the bass line. The car died in idle and then the idle went up and down between 1&2000 rpm but has now stopped. Can I put a bigger battery than stock with out any issues with the altenater or electrical systems?
Also my hand brake light goes off but then comes back on while I'm driving?

do you play music much with car not running?

How about putting a normal battery and a smaller radio. Those Earth shaking stereos are nothing but problems to electrical systems. A bigger battery is not going to solve your problems.

Thankyou for your most unhelpful reply doesn't really answer my question does it!

Only if you don't want to face the truth. A bigger battery will not resolve your issues. You are overloading the electrical circuit and the battery is only the beginning of your problems. You're consuming more current that the system can maintain or safely carry.

Ok so I'm not running it now. And I'm still having electrical issues. Car died and now the passenger window won't go up? And I took a look at my fuse box and their is a wire going into the parking brake?

I don't know what all your electrical issues are. That could be a whole new set of problems. Have your battery tested and if it's bad, replace it. Batteries are dimensioned by a group number. This one takes a group #42 so look for the longest term battery in that group size and that's the best battery you can put in it without modifications.

Ok thanks I think ill just replace the currant battery and use it for the stereo.

Ok I got a new battery. I've shut down the stereo so its not running now.
My engine light went off but then came back on? The code is for fuel management system?