I say 'buy the magnets'. you never know, it might handle better when going over metal bridges as well, they'll SUCK you to the road making them good in a strong crosswind........and if you believe that, then you really had better buy the magnets.
As for peak torque, most manufacturers tune their cars to attain peak economic performance around 56-60 miles per hour (does that sound like 2k rpm or their abouts by chance?)