I'm actually planning a turbo setup on my '88 300E (as well as a 5-speed conversion... I found an '86 300E being parted out and am currently in the process of negotiating for the transmission and pedal assembly, and possibly the hydraulics as well), and did some relatively extensive research on the Mosselman turbo kits. The most I found was that they used twin Garrett T25 turbos (no detailed specs unfortunately). I'm bookmarking this thread because I'm hell-bent on turbocharging my 300E. However, I must say that 450 hp is a bit hopeful on only 6 psi (the Mosselman kit pushes 6 psi on stock internals and squeezes just shy of 300 hp out of the 103, something like 320 out of the 104). I hope you're going a bit farther to achieve the 400+ mark