- The piston is 87mm, which can be 1mm much larger compared to the common 86mm, and the fabric is light-weight and robust A4032 solid aluminum alloy. The desired clearance of 0.It’s not unheard of for GT-R fanatics to sidetrack and focus on Z-tunes and 400Rs. Supporters of your brand name are thoroughly aware of those confined-run GT-Rs and the s