wiredup

Thats what I plan on doing. The original tires are pretty expensive compared to most aftermarket tires (my opinion). So, when we need to replace ours, I will do some shopping, and ask a ton of questions before I drop coin on any tire.
Take it easy.

Topbanana

Don't know if it is of any help, due to the fact the company (Discount Tire) is American, but maybe a local (or big chain) shop in you area can perform the same proceedure. When I was trail running with fellows from the NAXJA in Northern Michigan (the UPee). They have this company "sip" their mud tires for winter running. (Info site is www.discounttire.com/dtcs/tireSiping.dos) I have access to this company (living right on the border) and have bought tires from them (great to deal with) but have yet to inquire about the proceedure or cost.

JTPhoto JK

I ran 2 winters on 35" ProComp Xtreme M/T and they were alright, awesome in deep snow and just OK on ice and hardpack. This year I have 35" GoodYear Duratracs. The Duratracs so far seem to be much better then the ProComps and def better then the stock crap.. Duratracs can be studded...
I purchase all my tires from the US from tirepackages.com because our local tire shops refuse to come even close to the US price. Don't get me wrong here, I am all for shopping Canadian, but $1000 difference for the same set of tires and rims is a little hard to overlook...