As it stands, I see no point in having what would essentially be two modes of transit (subway, LRT) for Sheppard E and an altogether different mode of transit for Sheppard W. If the funds were limited and the Sheppard subway can't be completed at some reasonable time in the future then I think conversion should be considered. Particularly, since the costs are likely to be reasonable enough to allow an extension to Downsview for that price. I am quite skeptical that the extra 6 mins would significantly deter anyone from taking a Sheppard LRT. For the cost of completing the Sheppard subway to STC, we could LRT most of Sheppard from at least Downsview to Morningside. Extending the subway to STC is estimated at 1.7 billion. Conversion according to Soberman would be in the half billion range. So for 1.7 billion we could buy 30 km of LRT infrastructure. If the funds aren't forthcoming to finish Sheppard (and Metrolinx does not seem to think so), I think this a great option to extend service to most of Sheppard.