i left the factory sound deadening in. the herculiner sticks real well. there is no sign of peeling or anything after almost two years. you can throw almost anything in there too. spray in liner is the best way to go but they want at least 600 bucks to do your cab. my friend was quoted by line-x for $800 to spray the interior of a standard cab toyota.

87 22R PU, 2? body lift, 33? BFG muds, 4.88's, F&R Lock-Rights, Rancho Shocks, EB's Street RV Head w/ 268 Cam, LCE Header, 2" to 2 1/4" exhaust, Flowmaster 50 series, Magnaflow high flow cat, complete Herculined SR5 interior, V6 BB, MC, and calipers.