||not a sequential but you get a closer ratio, better durability, more gear options, and able to GET PARTS if something breaks. With people making 6 speed conversion kits for our Z's the transformation is pretty straight forward, I should know, I did it myself and would never go back to the factory 5 speed.
If you get the close ratio gear T56 option combined with a 4:10 rear end ratio is a stellar combo. I added a specialtyz lightened flywheel, and a carbon fiber single piece driveshaft from the driveshaft shop. All of that rotational weight loss is VERY noticeable. It reminds me the snappiness of a higher compression N/A engine. The turbos stay spooled on the track no problem, you only drop about 1k rpm when you shift.
Driving on the interstate with the cruise set I get about 24 mpg!!! When racing at Road America I get about 4-6 mpg!!! Thats about a gallon a lap, lol....