Jon,
I was a die hard Simpson fan for years but I bought once my Vudo while out I purchased a Bell GTX (The next upgrade from the K1) and I now have 2!! They fit great and I've had no lifting or buffeting while wearing it.
Like you said, money is tight but don't take a short cut in the helmet department. The GTX is perfect for midgets and sprintcars and well worth the money.
http://www.bellracing.com/public/ind...duct/detail/9/