I thought I would post my recent findings as its getting to the time all 07 and 08 owners are going to be looking to replace the stock battery. Initially I was looking for the cheapest solution (may be looking to lemon the car b/c of faulty motor mounts), but came across not just a cheaper battery but a significant upgrade as well. The stock Nissan batt looks to be a group 26R and approx 500-550 CCA. Replacements come up as 26R or 35. If price is not a big deal then just go with the Optima Red Top.
I found a list of battery groups and dimensions (
http://www.electricfence-online.co.uk/s ... chart.html) and went to town in excel figuring out all viable options.
To cut to the chase the best upgrade and value is the Group 24F. I did some investigating and found the Wallmart MAXX-24FN battery (which are rated highly) had all the right dimensions and the most CCA for cheaper than the Group 35 batts. This sucker is about 10"x6.5"x8.5" so it literally is the largest battery that will fit in the tray. It sells for $79.97 and packs 750 CCA! I'm installing it within the next few days so I'll follow up and post some pictures if all goes well.
For those who are interested here is all battery groups that probably will fit and have the terminals on the correct sides (Keeping in mind the group numbers only define the maximum dimensions for L, W, and H... so bring a tape measure to the store):
42, 96R, 90, 47, 97R, 26R, 34R, 85, 22F, 54, 55, 56, 61, 62, 63, 35, 24F
BTW as I measured, the battery tray seems to be able to accommodate max 10.25" x 6.75" and the height I would say no more than 8.75" or maybe 9", although this is difficult to measure (hood clearance).
I measured the tray and came up with the
Let me know if you would like me to post the consolidated spreadsheet.