what kind of aftermarket coolant can i use for my wrx? Here in hawaii the dealers don't carry factory coolant and I try order from subaruparts but they say they can't ship coolant because of some safety hazard.

 

The Peak Global is suitable for Subarus (and is actually compatible with all vehicles). Silicate and phosphate free, and it will mix safely with any remaining OEM coolant. Not sure about availability down there in HI, but up here in NY it can be bought in a 50-50 premix which is very convenient, no need to mix w/water. This is what I used to service my cooling system several months ago.
It is rated for extended drain interval (5yr/150K) but only when used in a system that was either factory equipped with extended life coolant, or when the system has been totally flushed of all old standard coolant. When used for a standard drain-and-fill service in a system with regular coolant, it will still need to be drained at the original interval.
Also Prestone has recently introduced a similar product which may be acceptable to use.