Yea the cold start thing is still an issue but it really only lasts for about 2 minutes and then it's fine. On that note, Gt287 a friend of mine suggested I use an electronic boost controller setup (or basically just an electronic valve) that I could even set up for more than one setting (cold start, warm engine, throttle, etc). Haven't though about it too much since I'm broke but I think it would be neat (although expensive) to give something like that a try.
I think it would be a little tricky to actually run a vacuum line through the cabin. I think the engine would have trouble getting the air in that situation just because of the length and curviness of hose that would be required. I am sure you could do some sort of crazy mechanical switch though using more lines if you thought about it hard enough haha.