Spectre
The Deported
- Joined
- Feb 1, 2007
- Messages
- 36,832
- Location
- Dallas, Texas
- Car(s)
- 00 4Runner | 02 919 | 87 XJ6 | 86 CB700SC
There's more to insulate, probably - around here limits for a car are 74dBA "driving noise", that's at 3/4 revs in 2nd or 3rd under 50km/h at full throttle.
Quick googling about the US was inconclusive, some sources state 95dB - that would be one hundred times as loud. If true then no wonder you need more noise insulation. Probably some different measurement though.
Most likely, considering that the Series III was quieter on the outside with the Federal spec mufflers than the Euro/ROW ones, to use one example I am personally familiar with. They also sometimes came with insulation that was optional or simply wasn't available for Europe.