Originally Posted by: SnoButchR 
Tremendous thanks. Wish i would have explored the forum before FMS7 and found this tool in the time of FMS3, but will take full benefit now. Question: what should one input for non-adjustable parts?
For example the 2018 911 GT2 RS does not allow the installation of either of the spoiler upgrades w/o exceeding the class restrictions. Therefore i don't know what to enter for front and rear downforce. Is it possible to get reliable numbers from the spreadsheet for this vehicle? If not the spreadsheet is still a valuable tool just hoping to increase its usefulness.
That's great dude glad you getting on with it so well. With regards to what you said about aero, you can still use a value if you wish or to keep it simple put it at 0.
But I have played around with this before because even without wings the car will still produce a little downforce. Try a range between 25 to 50, just have a little play in this case and find what best suits the car.
Let me know how you get on. 👍😊