Good Morning All!
alcheng - the rims look great. For some reason I didn't realize you had a roadster.
Here's my two cents on the spacer/springs discussion. Get the spacers first. Decide how much you want the tires to move out and then do a little research. Ken is an excellent source for sizing once he knows the offset and how much "poke" you want. He pretty much nailed mine sight unseen.
As far as springs go, what you use your car for should be a big determining factor in the decision. As much as I loved my Tanabes and the drop it gave me, it was just too impratical for a daily driver in the area of Houston where I drive.
I don't know what your situation is, or what look you are going for with your car, but from the pictures posted above, it looks pretty classy.
Your ride will be compromised by the drop. I picked-up on a comment that Ken had made in another thread about the fact that you lose shock damping when you drop. I knew my ride was harsher with the Tanabes, but didn't realize to what degree until I had the original springs re-installed.
All of this is very subjective; it's your car and your money. It can also be a very expensive lesson if you don't do your research. I was very fortunate that my dealer comped the switch back to the original set-up, otherwise I'd have a much bigger hole in my wallet right now.
Don't get me wrong guys - I love the drops and the handling improvements and the look that comes with it. In my individual situation, it just wasn't the right thing to do. Just keep in mind that everything we do has consequences and complications we sometime don't think of when we get caught up in the excitement of modding. No one is more guilty of that than me.
Again, your car is beautiful and I wish you good luck with your mod decisions. Just be sure to post a lot of pictures so we can hitch a ride along with you.
Cheers!