So what issues might I run into with this setup? I'm thinking of swapping a set of current spec FM springs onto an NB sport setup and bolting them into my NA. This includes NB mounts and FCM bumpstops. This is kind of a stopgap setup I might run for a year or so.
I'm all ready to do this but then read some older posts where Shaikh advised against the NB Bilsteins on an NA. Anybody running this configuration?

 

OK...realizing that NA and NB springs are different. I was thinking the FM pieces were the same for both. This doesn't look promising. Can this work at all with the NA springs? I'm guessing I may be back to the drawing board.....

 

Get NA spring mounts

 

I have hard NB Bilsteins on my NA with NA springs and NB tophats. What egg zachary did you want to know?

 

Well I think I've effectively abandoned this scheme for now in favor of just replacing my 1 blown Tokico.

However I would still like to know how you have the NA spring on there? Did you do as Brain said and install NA perches? I didn't realize that was an option. How do you like that configuration? I've read that the Hard S (I'm assuming that's what is on the NB Sport setup) with the FM springs would be very under-damped, true?

 

IIRC the NA springs have flat tops and bottoms and the NB's coils hang out on the ends. The NA springs worked fine on NB mounts but the opposite wouldn't do as well.

 

Nope. The various NB bilsteins have a lot of low-speed rebound force, suitable for autocrossing and other spirited performance driving on stock springs where a heavily overdamped setup is desirable. However, once you get into heavier spring rates (where the shock should actually be softer as the spring does the work now), the result is a very overdamped setup.

Driving my car with 500/350 on MSM bilsteins it's pretty obvious the low speed is too stiff and everything else is pretty close.

 

This contradicts everything I think I know about dampers, which is admittedly not a lot.

 

Yep, that's how the springs are. Makes sense and I even thought it might work. Ah, well. I figured with Bernie so backed up right now, I'd go with what I knew and keep savin' my pennies for good coilovers.