I think mods will limit resale buyers. There are quite a few people who will not buy a vehicle that has mods, especially lift kits. You never know the quality of the parts, who installed it and if it was installed properly.
That sucks, but that is always why you should contact your insurance company whenever you are in an accident, regardless who is at fault, in my opinion. Let them deal with crap like this. They'll fix your vehicle, and then go back to the other insurance company to get reinbursed. Yes, you are...
UGh. I've heard bad things about dealing with Geico, but luckily have not had to do so myself. Best to let your insurance company go after them. Thats what you pay them for.