insurance bla bla
Drove a blown 90 LX vert thru several winters in Colorado. Higher bias Eaton posi could be a little dicey on ice, but for the most part, drove sane in snow and it worked fine.
The following is lengthy, so here is a synopsis: It may be worth the read if you are seriously considering "specialty agreed value policy" insurance or "replacement cost value" policy. If you aren't interested in either of those things, suggest you print this post and use it for arse wipe.

And click out.
Shark is on specialty "agreed value" policy about 15k higher than book value due to all the mods, so limited use. About 300 a year with high liability limits as well. As others said, have to show another DD (98 Buick beater in my case) AND is supposedly mainly for car club events only; not grocery getter. But when isn't there a Mustang show going on somewhere? Was I headed there?
Well, just sayin' on specialty insurance to look into details and decide if you can live with limitations or not. Way cheaper insurance and for shark and it is probably ok since car gets way less than the 5k a year I estimated on the application. If you decide to go with specialty insurance, suggest you make the yearly mileage as accurate as possible. However, I have heard that if you estimate over 7500 or 10000 on specialty insurance app with some companies, they'll tell you to piss off. Can't prove it, though.
Non-routine usage I would frequently cite if something happens and would be true: Test driving for recent "repairs". Well, new gears and diff rebuild is new repairs and needs test driven/broken in before anyone would trust it for a trip, right? New cam drive hardware and TSS pump? Repairs; needs tested, etc.
Not sure if that would float, but I'm always feeding shark more chum (money), so I doubt there would ever be a time when something isn't being tested or broken in..
"...well, I wanted to go to the 'Mustang Destroyers of GM Meet" but I had to first test and break in my new flux capacitor "repair", so that's why 3 cops saw me flip the car while burning the tires sideways at 50 mph..." perish the thought, but lol anyway. ;-)
I've read that "agreed value" policy is far superior to "replacement cost" policy. While either sounds much better than ACV (actual cash value - the typical widespread mundane car insurance policy) policy, agreed value has proof AND agreement of value to be paid in total loss done when you FIRST BUY THE POLICY - that is, in advance of any claim. A few hoops to jump though.
However, I've heard that replacement cost can be fought down to low total loss values much similar to ACV though with different tactics to make it happen - and it won't happen until you make a claim so it is lying in wait like a totally unknown thing; a goddamned trap. Numerous trap door clauses in those policies that I saw.
I think: Best to have agreed value in advance. Helps me sleep at night with my idiotic investment in shark, gold digging predator that she is. However, there are severe limitations on usage in such policies and only you can decide if you'll accept those or not.
Value can be raised each year though it does so about 2% automatically unless declined. More increase only requires a few documents and/or snap shots to get approval in writing - and a bit higher premium, of course.