Note: This procedure involves editing a game file; create a backup 
copy of the file before proceeding. Use a text editor to edit the 
"builds.csv" file in the "game\data" folder. 
The format for the parts is ID TAG, NICK, COST, WEIGHT, POWER FACTOR,
NOISE FACTOR, DEPENDABILITY FACTOR, PASSENGERS, CONSUMPTION FACTOR. 
You can edit the settings to your satisfaction.