I didn't use the Dynamat when I installed my MGW and I have no NHV. My car only has 750 miles (300 miles on the shifter) and I'm very happy with it so far, but I think the transmission and shifter could use more breaking in.
'14 Grabber Blue
GT - Base 300A, Track Pack, Recaro seats - Mods: SCT X4, BBK long tubes and X-pipe, Roush axlebacks, MGW shifter, BMR LCAs and UCA w/ mount
'93 Reef Blue
LX 5.0 - 5-speed, black interior, factory A/C delete - GT40P Top End, 5-Lug/4-Wheel Disc - SOLD