LTZ 50 MOD

My son has a 2006 LTZ50 which recently had a stator burn up taking out the CDI with it. I am having the local Suzuki dealer replace the stator, but I want to replace the CDI with something other than stock to improve the power. I have had the cluth modified which increased top speed but thers is no torque for the hills. CT racing has a CDI they claim will inprove power but is advertised with their pipe and filter as a kit improvement. I have also read that a 2007 Z90 CDI will iwork also and improve power without the stalling issues of the CT racing CDI. Can anyone help with which is my best choice? I am looking for what ever is best and easist (meaing no other mods needed)since I am rather clueless about mechanical things.