Welcome to the site
UniqueAngle!
You mentioned that you have had most of the exhaust system replaced? Did this include the catalytic converters? It is possible that if one of the primary cats or the secondary cat has gone bad, the exhaust smell could be due to that.
Also, do you know if the dealer inspected your exhaust mainfold/ headers? This is the part of the exhaust that hooks right up to the exhaust ports on the side of the engine. A crack in a header could also cause the smell.
Good luck with the fix...and enjoy your SVX!!!