hi all after building my boat 4.9mt tiler 50hp 4stroke on it, not to heavy, my AU1 seems to be haveing trouble towing it,its allright untill i start getting over 80kmh, i dont live far from my local boat ramp thats ok but im wanting to tow it further up the road on holidays,boat motor trailer is around 700kg, so what size boat dose everyone tow with what car and how do you go at 100kmh and any suggestions.