Does anyone know if there is a diffuser for the GTT

Greetings

 

Zero Sports do a rear diffuser (if that's what you mean just as Aqua.

http://www.aqua-fsp.com/

http://www.zerosports.co.jp/

Can't read Japanese? too bad, mate you should or else you'll never find the real good stuff for your car... anyway you should ba able to find the Zerosports one as the site is almost in English.