That 7 speed transmission is very reliable. The 400hp version also use the same transmission. I also think the transmission should also be good for 500hp tuned version if you flush its transmission oil(10 quarts) every 50K kms.
My son's 2007 G35S has very similar transmission but only 5 speed. After 200K kms the transmission has ZERO issue and still shifts as smooth as my 2017 GSF's 8 speed transmission!!!