Ix37

I wouldn't go for something which is only in the name automotive related. Avoid cheap crap and focus on butyl based products. The thickest I have found was StP Gold (2.5mm thick 17sq ft at £55)later on StP Silver 2.2mm thick (only available in bulks), next would be damplifier pro 2mm thick 16sq ft @ 75quid, next should be Dynamat Extreme door kit 12sq ft at £80 - 1.7mm thick, last one in that chart is FATMAT Xtreme 1.15mm thick 20 sq ft - £65 Hope it helps I used Dynamat in the past now my vote is for the stp