im pretty sure no bodies up, but i remember that
 

if you have stock sport suspension, all you have to change is either the shocks, or the springs.
the problem is i dont remember which one. can you help me?

Well, I am up. =). I would change both if you are going to lower the car.

do you mean the neuspeed/bilstein shocks?...
 

quite a few people on the forum have used the stock sport springs and the neuspeed/bilstein dampers, which have multiple settings for the spring perches and can be used with stock or aftermarket springs. so far as i can tell, using the stock shocks and lowering springs will blow the shocks fairly fast

I second that, do both ;)

Right: changing both is better, but....
 

his question is if you only change one, which? I'm interested as well. Anyone know?

What is it that you want to achieve?
 

I assume lower the car. If thats the case than with your sport suspension you can change your springs to get the lowering effect. I do not recommend it as the spring rates will not match your sport shock which could potentially blow a shock. Also, research the springs as some springs will not lower your car at all. I guess it's a matter of personal preference but by all means go for it and post your results;)

i've seen people just do the springs
 

As long as you have sport package you can temporarily run stock shocks.

You can keep the sport springs, and run them with aftermarket shocks.
 

You can run new springs with the oem sport shocks, but you will have to change them in time. Then you will have to pay for two suspension installs, unless you are doing it yourself. I am currently running oem sport springs with neuspeed/bilsteins(lowest perch), and it is a significant improvement over stock, not to mention a nice little drop from oem sport height. This obviously wouldn't be an ideal track setup, but it is a nice compromise from oem sport. I've been told that the oem sport springs feel about as firm as h&r sports, and maybe a little firmer than eibachs. Again, this is what I've heard, and I haven't driven each of these setups back to back to give my own opinion. If you don't mind spending the extra $250 bucks for new springs, then go for it.

some people kept the sport springs and changed the shocks to the bilstiens