Does sound like an interesting game.
As others have said the issue will be with pulling down the data, as it's not using texturised 3D models.
A side issue with using Google Street View for a 3D first person shooter is that some places will have lots of people in them... and those people will effectively be "art work".
As an alternative suggestion, would it be possible to use something more like the 3d Buildings of Google Earth (but using the Textured ones, rather than the Gray ones)? Doing this would remove the issues of other people and objects already in the scene, and allow for better loading ahead (but then I'm not completely sure of what your game is meant to do)
The raw speed of JavaScript execution actually has little to do with it. It's mostly the images and other data that gets lazily loaded that's the bottleneck, and there isn't much you can do about that. – Sasha Chedygov – 2009-09-23T03:51:08.320