Thought I'd post this here, for use/discussion/constructive criticism etc.
It's a suspension dynamics calculator, which calculates roll angles and load transfers, allowing you to see how changes to the vehicle set up affect them. The 'magic number' is the Front Lateral Load Transfer Distribution (FLLTD) which is the portion of the total load transfer that is taken by the front axle. Since we know that tyre load sensitivity dictates that a load differential across an axle pair results in a reduction in the total lateral tractive force of that axle pair, we can take this number as an indication of a cars tendency to understeer, with a higher percentage meaning more understeer.
http://blackartracing.zxq.net/Load%20Transfer%202.php
There are DC2 and MX5 versions in the sidebar.
It won't work on Internet Explorer, some mobile devices may not render it correctly and if you have an over zealous AV program installed it might accuse it of being a spam site. I assure you it is not, I wrote it myself and all it is is some HTML, PHP and JavaScript.