I have asked about this several times on the classical pontiac site and also talked to a distributor of both Soft seal and Metro products, wich I think are the two main manufactures. The consences is both are good. I belive the Metro is more spongy like the facory and Soft seal is more rubery, takes longer to seat, cost a little more but is more durable.

I haven't bought mine kit yet so can anyone confirm this?