Nice ride - was looking at the SLT myself. But ended up w/ a P2 instead when they had their sick sale a few months back. My buddy was wanting a new ride as well and the buy 2 get 2k back was too good to pass up.
If its between the SLT or the SDR - and if $$$ is'nt an object - go w/ the SDR.

Main diff between the 2 is the components - Ultrega vs Dura Ace.
Need to ask is the grand difference worth the 8oz you lose w/ thje dura ace.
Either way - nice bike porn