Yes, as a matter of fact I have probably played way too much Tokyo Xtreme Racer 3. Green line is the C1, light blue is the existing Tokyo track in GT. Either direction is acceptable to me. Credit for the image goes to GTP user "twitcher" AFAIK. The Yokohama loop seen in TXR3 would be cool (and a lot faster) but unless a couple new onramps have been added between Daikoku and Yokohane lines, there's no way to actually make it a loop.