Finding a racing boot?????? more like finding someone to fit a racing boot-----where do you live?
what size feet in centimeters?
read through the above article and find out how to do a "shell check" on any boot you might buy and any reputable boot fitter would do the same so, if they don't do that first-----run!!!
the only way you can do your own "boot fitting" is if you have worked as a boot fitter for years (plural) and become a good boot fitter your self. If that is the case then go for it.
there is a list of great boot fitters at the top of "Ask the boot guy's under "Who's who in ask the boot guy's, see if anyone is near you.