Try contacting Autocad. They will give you one in exchange for some money
"AutoCAD® 2008, scheduled for a March 2007 release, is compatible with the 32-bit and 64-bit versions of Windows Vista™ Home Basic, Home Premium, Ultimate, Business and Enterprise. AutoCAD LT® 2008, also scheduled for release in March, is compatible with the 32-bit versions of Windows Vista Home Basic, Home Premium, Ultimate, Business and Enterprise.
There will be an AutoCAD 2007 and AutoCAD LT 2007 update released shortly that adds support for Windows Vista 32-bit versions.
Visit www.autodesk.com/support for updates on Windows Vista support."
i know mate ive bin talking to a guy on the web from america and he was telling me about this conversion he was doing and how when he designed his inlet he had to have it flow tested so he could get an even airflow through each port and so he could work out how big the plemum had to be to give maximum flow.
he also told me that the car he was building had no problem producing power that it was torque that was the problem and that how he got over it was he made the tubes wider at the top wich improved torque throughout the rev range