I can answer somewhat to the chopper call, ive had the same issue, i think its just an unsolved issue mate, Sometimes if i call an ambulance fire or chopper itl crash out, heck the recent crashes ive had involved calling transport, double check ELS.ini, make sure all cars that dont have ELS lights are numberd to 0 this way you wont crash because of ELS, only ELS enabled cars should have it enabled on the .ini file mate. Make sure all your mods are installed properly, such as LCPDFR in the "script" folder, along with all other mods "expetion to the ELS files", Car mods can cause issues but only really because of ELS refer to the first bit of what i said.
I run RC2 my self, had some issues but have surpassed most of them as being ELS or car mod related.
You said it, the only reason why it is so expensive is because it uses special metals such as "magnesium alloy". And the specs pretty much are shit. So don't buy alien ware computer get an "Hp pavilion elite" if you get like the "Hp Phoenix" which literally slices the alien-wares computer price in half, its 2x better and runs GTA IV on high setting pretty efficiently.