A Senior Review commissioned in 2006 by the National Science Foundation's Division of Astronomical Sciences lauded the VLBA as a unique facility, but recommended that outside funding assistance be obtained for operations by 2011, or else that the VLBA be closed. NRAO is confident of its ability to attract this funding, and has embarked on a VLBA Sensitivity Upgrade project to significantly enhance the VLBA's capabilities. This project's goal is to achieve a 4 Gigabit per second (Gbps) capability by 2011, for the entire data path downsteam from the IFs. This is a 32-fold increase over the sustainable data rate of 128 Megabits per second (Mbps) available when the instrument was inaugurated, and 8 times the current standard data rate. The 4-Gbps data rate corresponds to an RF bandwidth of 500 MHz per polarization, and will enhance the signal/noise ratio of the typical continuum observation by factors of 2.8-5.6. The latter is equivalent to nearly two optical magnitudes. New technologies for digital backends, data transmission and recording, and data correlation, make this an achievable goal for a fairly modest investment. The first element of this development, described in Section 7, is already in routine operational use. Overviews of the VLBA sensitivity upgrade are given by Romney (2007) and Walker et al. (2007b).