I'm here to help...
ALL ABOUT SIPING:
I just bought new BFG All-Terrain T/A KO'* in 30-9.50x15 (full set of 5) for my '92 GMC Jimmy 4x4. I had them 'siped'.
I'll probably be going in to have my GoodYear NASCAR Eagle#1 235/55R16 tires on the Bonneville SSE done in the next couple of weeks. These are great tires for the Bonneville. Good ratings, even in the snow, but even better if they're siped.
This is a GOOD THING to do to your tires.
Go to the HISTORY section to learn why they call them 'siped'... :o
Go to the PRESS section to learn about the WARRANTY aspect.
CHECK OUT all the links and read the articles and look at the pictures.
There'* a LOT of information on this site, even if you decide not to get the procedure done to your tires.