Tein are one of the top spring co's in Japan and every "Import Tuner" in the U.S. lusts after them. They offer full coil overs with EDFC (electronic damping force controller) so you can adjust the compression and rebound from inside the cabin (not for the Q however).
The New SR Special shocks avail in Jpn. should be as good as the Tokico Blues (< I ran the blues in my Si and they are in my wife's Accord Wagon, good shocks).
No idea about the G50 parts, but I bet that they do since they are a Japanese company and VIP cars are popular to hook up in Jpn. Look on
http://www.tein.com/ and if you can't find them, send them an email with your question.