I took Dave Shannon's advice from his website and put the viscoelastic stuff from mcmaster in my 245 this weekend. Also pulled several Volvo mats from under the carpet of some 240s at the boneyard. All in all, the job is pretty easy, just 4 bolts per seat and a few other things and the carpet comes out. The viscoelastic stuff is super-easy to use and I covered the whole floor with several layers on the front passenger floor and as much as I could reach on the firewall. Combined with the diesel under-dash mats I recently found at the boneyard and my IPD hood-quiet kit, my 245 is pretty darn quiet now, although I think a worn-out muffler may be part of the problem. I'd suggest doing it if you haven't already. I'd buy 4 sheets and 5 if you want to rest assured you'll have plenty. Also, it's a great chance to look for any rust on the floor and take care of it.