My bike has an ultegra 6700 setup with a triple crank. I thought I would need a triple living in the mountains but I don't like it anymore. I want to get a compact double ultegra. So My question is what can I get away with not replacing. I know I should technically get a new brifter, front derailleur, rear derailleur, and new chain. Could I just limit the front derailleur and shorten the chain and still have good performance from the drive train?