Ok, I've been talking to Ryan over at Stasis about different coil over options and have pretty much settled on the Track Sport kit they have, but I'm still hazy on what the numbers mean and how they translate from spring rates into english. This is what he told me:

"Below freeway speeds, the Track Sport kit is not really that much more harsh than the Street Sport or OEM, but the roll reduction is still there. Typically for customers that do a lot of freeway driving, I recommend the 550/600 or 550/650 setup to aid in freeway compliance with the trade off being body roll compared to the normal 600/700 setup that most Track Sport customers run, or even the 700/800 which is the next most common spring setup for the S4."

I understand the gist of what he is saying, but would like to understand what the numbers mean in more detail. Anyone want to take a shot at this?

 

well I do believe those numbers indicate the pounds per square inch of the spring - how much weight/pressure it takes to compress them. The higher the number, the less body roll, but also the harsher the ride.

700/800 is an insanly harsh ride on an A4.

 

Ditto what brrman said.

 

So do you guys think I should go with the 550/600 like he said or the 600/700?

And for anyone interested I might facilitate a group buy on these sometime pretty soon to knock down the price on 'em.

 

If you use your car for a daily driver 550/600 is fine.

My Neuspeed race springs were 560. Crap man they were stiff.

 

haha yah my intrax are like 600 from what I can find.. there pretty stiff
Yeah the S4 is heavier than the A4 so it needs a little more boing!

if the guy starts talking bout progresive spring rates that just means that as they compress they take more force to compress further