Quick-Start is an experimental extension for the Transmission Control Protocol (TCP) that allows to speed up best effort data transfers. With Quick-Start, TCP hosts can request permission from the routers along a network path to send at a higher rate than allowed by the default TCP congestion control. The explicit router feedback avoids the time-consuming capacity probing by the TCP slow-start and is therefore particularly benefitial for underutilized paths with a high bandwidth-delay product, which exist in broadband wide area, mobile, and satellite networks. In this paper, we first introduce the Quick-Start TCP extension and survey other related approaches. As our main contribution, we evaluate the performance improvement of the Quick-Start TCP enhancement compared to the standard TCP slow-start mechanism, both by an analytical model and by simulation results. Our initial investigations confirm that that Quick-Start can significantly reduce the completion times of mid-sized data transfers. Finally, we address some of the open issues of Quick-Start that require further investigation.