Small Battery's? Anyone have any experience?

A kind menber has suggested a few different makes of batteries to use in my KZ750 Twin, i thought i had my mind made up on a Shorai but i thought id seek some advice 1st as i have more choices.
My bike is being built into a cafe racer so i really want as small as i can get as it will have to be concealed. My bike MUST run a battery to power the field coil so a Capacitor is out of the question.

So, does anyone have any knowledge or experience of any of these?

MFolks wrote: Motorcycle Batteries
www.ballisticparts.com/
www.shoraipower.com/
www.motydesign.com/8cell_prod.php
alienmotion.com/

Suggestions on which 'model' in each range to go for are welcome too.

I know the guys over on ZRXOA.com really like the shoria batteries. The one they use is only 1.68 pounds and a lot of them use them on big bore high compression motors. The guy at www.expensivelightweightstuff.com sells them for 100-154 with free shipping in the US.

Yeah they seem good. I believe someone did mention a violent fire with one of them 1 time though. Seems all of those new batteries need a special charger too.

I have heard some good things about the ballistics, will probably go that route on my other bike soon