Get in touch with FC Performance or Flea here, he helped me map my car "remotely" here in Sweden. Some rolling road session's, a bit of mail correspondence with jpeg's with all figure's, and pretty soon I had a good working map.
I don't have any external boost controller either (it's all in the chip) so that might be a thing for you?
what has your max boost been set to then per??
Less hassle I know but I like to be able to ajust the boost, low for around town and max for track private roads! Lol