Well acutally, this is what u have to do. Go to '' http://www.tomsracing.co.jp/e/comp/lexus/g...ng/89840-t.html ". That link should be the direct site to the product. The speed limiter problem u have is considered an air cut off.
http://www.tomsracing.co.jp/e/comp/lexus/gs50/engine.html, this one should bring you to the porducts page for Tom's Racing in japan.
Oh, and by the way, does anyone know the Hp rating for the stock transmission on the gs300 and 350 ( same transmission).