whats the best idea when choosing a battery for a zx10r.
should you just buy a zx10r kawi battery or is there a better way like small car battery or other.
thanks.

Standard car battery every time. The battery is only used to start the engine after all, after that it's the alternator doing the work.... The only advantage potentially of using a small car battery is that bike batteries appear to be a bit high maintainance (ie optimates etc etc). Car batteries are heavier but appear to be a bit resiliant...

Red Top 25 on mine, is a replacement for a Buell and has perfomed faultlessly on my zetec during the build and on the road now for nearly 2 years.

I'm using a 19Ah bike battery on my CEC without issue. So any bike battery with enough poke should be fine.

Ive gone for a powervamp 25 gel battery smaller and lighter than standard lead acid car battery