I recently did this! I have Country Companies Ins, and I don't pay for comprehension, because I paid cash for the car, so they can't require me to do that.
The advantages are more than just financial. I love my smaller car. I have 7 kids, so I have had a Suburban for years! I switched to a VW TDI (diesel--clean, quiet, new diesel), and have ZERO regrets! I get great gas mileage, my insurance is about the same, but I find that I spend nothing on repairs, the maintenance is less, and I love having a smaller car that can park anywhere! LOVE MY CAR!
I recommend looking at different car insurance companies. Seriously. And check your numbers...do you need Comp? If so, why? And check your limits. The law requires $25K/$50K here in Oregon. I carry a little better than that. But, sometimes ins companies quote you at the $50K/100K limits. Don't let that happen. ;)
Good luck!