Your "DREAM" piece

If you could replace one component in your present system with a "dream" piece, regardless of price, that would be synergistic with your other components, what would you choose? Remember, don't pick a piece that you could not use with the rest of your other components, such as a SET amp because your speakers are not efficent enough or a pair of speakers that your present electronics could not drive to an optimum level because of not enough watts/current. My "dream" piece would be to replace my Pass Labs X-350.5 with the Pass Labs X/A-200 mono-block amps. It would "only" cost about another 20 grand, but this thread is a fantasy anyways, right! Hope just for fun you GON members will share your "dream" pieces with the rest of us. Thanks.