I worked for an industrial battery company for a long time and we did testing on them when they came out. They don't hold up in very cold temps. I ain't changing what works when it comes to batteries. Plus the fact I can still get any battery I want through them now that I'm kind of semi-retiring. Stick with the stock one you eat too much or fill it up too high or pack a little extra oil and your little meaningless 10 pounds is nothing
From my research and experience, at least for the lithium battery I bought, says it does very well in the cold. And from experience, unless you have a gel type battery the standard electrolyte/ water cell batteries do not hold up very well in the cold! FYI I maintain back up batteries and battery components at a Nuclear facility so I have a little background here! A lot of are engineers are looking closer at the lithium batteries as replacement for are wet cell types(changing any system, especially battery backup for safe shutdown in a Nuclear facility is almost next to impossible), that is the main reason we have not switched!
And yes, you will notice 13 lbs of less weight when it is at the "high" center of gravity where out batteries are located.
For sound of a aftermarket can, unless you really like hearing a Chainsaw in your ear for 200 miles a day, I would recommend the Diamond S! It's super light weight (check), sounds a lot better than stock, NOT obnoxious and ear piercing at WOT(check) and from dyno runs, makes a little extra power(check), plus looks awesome!
So am I missing something