Spike upgrade for Thiel 3.5's

I have the factory suppiled spikes but Im tweaking my system.
Im wondering what a good cone (or spike) would be to use to improve the performance of the 3.5's.
Im looking to tighter bass and better all around sound.BTW they sound great now,but as I mentioned Im doing some tweaking to my system.
Im 'kinda' leaning toward BRD cones but would appreciate any other ideas.I only need 6 cones/spikes.
My floor is a quite solid,wood suspended with thick pad and carpet.
I use Audiopoints http://www.audiopoints.com. They come anyway you want and in any thread size. They're really good!
Hi David - I use audiopoints under my 3.6's. Definite improvement, most noticably in transparency and more clear midrange. Mine are on an oriental carpet covering a concrete slab.
I use stale dumplings(at least 2 weeks old). Really tightens the bass and increases mid range clarity.

I have also tried the audiopoints under my 3.6, but my berber carpet and pad was too thick. Perhaps Audiopoint will consider manufacturing some carpet piercing spikes. Heard many good reviews, but will not work with thick pads.
Thanks for the info.
I'll look into the audiopoints.
Has anyone used BDR cones under their speakers?
Hey Pops,glad to see an 'old timer' still lurking here!