I think they make a big diferance , quiet down string noise well . Washington Hunter , I think the problem you are haveing is because your string is not twisted , as slvtech said
One put a few more twist in the string.Or two serve the string Leech in.
serveing it in should help , without changeing your cam index , or timeing . In the future you may consider changing to a twisted string as Im sure you'll gain speed that way , it will be quieter and you can posably use a peep without the rubber tubeing attached . Now is propably not the time to do it as season is around the corner and its best to leave you bow the way you are accustomed to shooting it this time of year .