Hey Dann,You can really only accomplish this with modded tracks. The way I know how to do it is in the .AIW file. The Reiza default AIW files are encrypted in the AMS.exe so they are inaccessible. In any modded track find the Worst, Mid, and Best Adjust lines in the AIW file and increase the values.
Example:
WorstAdjust=(1.00)
MidAdjust=(1.13)
BestAdjust=(1.28)
Hope this helps.