Originally Posted by Auto-X-ZTS
With all ude respect, the Z1 is without question a faster tire than the Falken...look at Nationals results. Its also been quantified elsewhere (see sccaforums.com). So is the RE01R, and so is the R1R...the Falken is a good local/regional tire that is "cheap"...but they are not tire to have at the more serious levels.
I agree with this statement. 615's are a good "budget" autocross tire. I ran on them this last year. Though they were good, they could have been much stickier as a street tire. I'm hearing the Z1's are alot better and will be trying this as my next set of street/autox tires. But I'm not sure I'll be autocrossing on them alot, as I plan on having R-compounds for next year.
Your KDW's are also fairly decent tires. Also not the greatest, they should still be a good street/autox tire. I'd wear those things out before worrying about them.
The secret to autocrossing is to basically make the track as straight as you can. Then you can carry the greatest amount of speed through all the elements. Your tires should screach, but should not howl. If they're howling, your pushing too hard, or turning the wheel too much.
The best way I know of of practicing during the winter is either racing in your local slush series, or dishing out a few hundred bucks and buy this
Two really good ways to help make you faster, is have someone with experience drive your car through the course with you as passenger, or registering for a local autocross school, if one's available. Aside from simple experience, these are the best ways to hone your skills.