Would s4 springs and shocks be a significant upgrade for my non-sport? If so, around how much $? thanks...

 

i want to know too, anybody knows? I wish i still have my S4 instead of A4 now.

 

Yes, they'll be a good upgrade. I'm running S4 springs for now (on non-sport OEM 2.8 shocks) and the ride firmness increase is noticeable. It's nowhere near uncomfortable - don't get me wrong there - but it feels much more buttoned-down and in control, and there's a noticeable change in the flatness of the car when cornering. By doing the struts as well, you'll allow the springs to work to their highest potential, and the combination of S4 struts/springs will bring your car down quite a bit lower than a non-sport suspension - you'll have about an inch of wheel gap or so, not much more than that, rather than 4" that the non-sport gives you. If you find a good deal on them, get them - you'll love 'em.