If you look at Felts webpage for your bike, it is spec'd with an 11-30 Cassette. That tells me that you most likely have the 105 GS RD which even though it is only rated as a 28 tooth max cog, it can definately handle a 30t and probably can handle a 32 without issue. I'm running an ultegra GS that easily takes my 32 tooth cassette. Ride your bike as is but if you have troubles go back and just have them try throwing an old 32 tooth cassette on just to make sure it will work. you should just need to screw your b screw in all the way.