Wow, thanks.
For the record, I'm comparing my experience in other non-IRS cars, which I have nothing against (for a street driven car, I don't think I can tell the difference). Most recent ride was a B5 Passat with Neuspeed Sports and Bilsteins, which has none of the nervousness in the rear, but the chassis is MUCH softer than the FiST and the wheelbase MUCH longer (exactly 10"? And also 16 year old suspension components contributing the the softness
)
To say the FiST is more planted and fun in everyway is a gross understatement and this is the first car I've ever owned where I have no idea how to improve upon it without destroying some other aspect. Still in the honeymoon period, maybe?
The car is far more capable as a car than I am as a driver. I may not do anything other than short shifter and 16" lightweight wheels and sports tires when the stock REs poop out. But I'm strongly leaning towards mild chassis stiffening as a "safe" next step (STREET package looks really attractive, maybe the rear lateral brace too).
Thanks for listening and thanks for the elaboration on the rear torsion bar purpose.