I needed a new battery for the Xj and wanted a good one for the first time. I was going to get an Optima yellow top because I wanted a high quality combination deep cycle/starting battery. After searching the D34m Blue top became my choice with its top post aux. terminals that are more convenient i.m.o. .
The D34m is the deep cycle version of the Blue top that is identical to the yellow only with top posts that are rated higher than the yellow tops side posts.
The 34m blue top is supposed to have the same relationship with the red top in that they are chemically the same only with different colored cases and different aux. terminals for your accessories.
Here is a link that confirms what I stated above excluding that the top terminals are rated for more, I never confirmed that. However I read it in more than one place while I was searching.
http://www.optimabatteries.com/en-u.../back-basics-optima-redtop-yellowtop-bluetop/
I also decided to get a nice charger to maintain the battery here is the thread where Ed and Grimm helped me decide what to get.
http://www.naxja.org/forum/showthread.php?t=1108475
I ended up getting a newer version of what Ed uses the C-tek Mus4.3 test and charge. It is the same as the older version but with added testing features.
"Three easy to use programs to test battery voltage, start power and alternator performance to provide a complete picture of battery and vehicle charging system health."
While I was at it I got some military style battery terminals with boots from Prime 4x4. They are awesome and I may get their rock lights some day.
Here you can see it all connected and the fused Pigtail that came with the charger and its covered plug. It also came with alligator clamps so I can use it elsewhere.
I have been super happy with these changes. My starter definitely cranks faster/harder and I am sure it handles the subwoofer better. I haven't run the winch yet but I wonder if it will be noticeably different, I suspect my old battery was no good for much longer than I thought and was limping by.
Between the military terminals and the aux terminals My wires came out real clean, I may spray some battery terminal protector to cover the aux. positive stud in case I drop a wrench or the battery ever came loose.
The charger has worked out great and I have used it a few times, it restored most of the capacity of one of my 5ah agm batteries for my rc crawlers. While a multi meter would make the tester unnecessary I have found it to be very convenient and will actually use the testing programs.