Jack21....
I have to agree with you!! I have a T5-Z behind my 408W and other than the gut wrenching torque in 3rd (which I have worried about), the trans has held up for a year!!
I install magnetic plugs in all fluid compartments in all of my cars and the T5-Z plug has never had any metal on it....So I must assume it is OK??!!
I don't race the car but know of a lot of folks that do and unless you miss gears, the old T5's even hold up well!!
I like mine but the OD is too tall.....0.63:1 gives me 65MPH at 1600 RPM's in 5th. May go to 4:10 gears later.
Jack