Well you could always drop $1500 or so on a classic auto air kit...then you can cruise anytime.
Those coopers must be really bad. My car is likely significantly more powerful than that one and the 225/60-15 BFG G-force Sports would hold on unless you were well into the carb secondaries. But those aren't total crap.
The Contis that I have now really worked well on my '04 Colorado Sport I5 5-speed. With the normal stock tires in the same width I could rip a 10' patch on the 1-2 shift every time. These tires barely chirp at 1-2. Haven't had an opportunity to test the complete grip of them on the Duster. It already seems a lot better. Not even a chirp out of those yet.