Well, with this particular driver the cone doesn't make contact with the spider until the edge of the cone touches the leads right near the terminals but that's well outside of the intended range of the driver. The thing about adding another spider is that it can also add more mechanical noise if it's done wrong. If you flip one of them so that they're mirrored, in theory you will cancel out any none linear restoring force that is applied and distortion will be lower. If you put both of them in the same orientation, you will double any noise associated with the spider and any non-linear force applied by the spider will remain.
The spacer for the OEM is quite tall and I found that the cone makes very hard contact with the top spider under very high excursion. Because the surround is so thick on the OEM, I decided to remove the top spider on mine and the problem no longer exists. The partnership of the stiff surround and the single stiff spider is sufficient to keep the coil in perfect alignment for 3"+ of travel which I use for deep extension rather than high output. There are ramifications for doing this which involve lowering the mechanical power handling and impacting specs such as Cms, Qms/Qts and Vas. I do not advocate doing this, especially if you want to beat the living daylights out of it. I did it to have an overall softer suspension and to allow for more overall travel without the cone touching the spider. Fs was also shifted downward a bit.my tc oem 10 has a very similar spacer, havent got to listen to it yet though
