RE: Peel and Seal
That is what I used throughout my '90 Westy and it seemed to work quite
well.  The 6" wide stuff.  And I wasn't that fussy putting it in, if you
pull the door panels and panel on the slider and rear hatch it ain't
pretty.  But it worked.  I have no experience to compare to the more
expensive stuff.  The biggest difference was made when I did the slider,
then the rear hatch, and then the front doors.
BTW, once this stuff is on it's on, it would be a real mess to try to
remove.
And I had absolutely no out gassing problems, I've never smelled anything
that made me think of the sound deadening material.