I guess the group 35 is recommended by most battery suppliers but some places like oreilly and napa say the 26r will fit as well
it looks like the 26r is smaller and less CCA
But if it works fine I dont see the problem
Also what brand is the best ? anyones with warranty and free replacement? I heard some places do that

 

Look for a 24F. It's a little bit bigger than the 35, but will give you more CCA and will fit without issues.

I went with the Costco Kirkland battery as it had the best warranty and is a rebranded Interstate, or so i have read.