Gas Octane level

O.K. Just wanted to know how to increase my octane levels to 98 or higher for my 75 280SL german version car. I read the manual and this is what she needs. It does have a catalyc converter. Here in CT our highest level is 93 or 94. someone told me to use racing octane booster, what do you think. does a lower octane ruin a car and make it ping more. Help.. I want to keep the engine running as long as possible.h