Underbody rust prevention/Tectyl etc
 

Anybody here have this kind of treatment done, and have any clue with regards to how much weight it adds?

Or if theres is any significant reduction in road noise because of it?

Mine will have this done to it before handover as it is very sought after with regards to resale price, no plans to use it much myself during the winter but roads here can be heavily salted to keep the ice away.

I've done it on my ae86. Yes, it reduces noise to a certain level but nothing spectacular. Don't know how much weight it adds. I put 2 coats on and 3 on areas that easily rust.

Chances are, for every area protected by the application, there is a gap or void in another area that makes rust formation more probable. So save your money.