I know the machine is just fine with the top and windshield but when you install the doors it gets very loud. I bought a bulk pack of dynamat xtreme and removed both rear and bottom seats and double layered it with dynamat. Also used some behind the legs. That took 8 18"x32" sheets to do that and it fit nicely and don't look to bad. I also installed sheet number 9 on the underneath side of the bed right over the engine. I installed one of the bed stall mats in the bed from tractor supply on top of the spray in bedliner. I wasn't sure at first if I was just wasting my money by doing this but now I think it was worth it. It made the cab much quieter inside and stopped a lot of the vibrations. I have around $190.00 in the mat and dynamat. I believe the dynamat is more of vibration eliminator than acoustic insulation but it is very thin and it fit very well behind the backrest and under the seat. Sometime I would like to use it underneath the hard top and see if that would help even more. I may be the only one that thinks it's loud inside the cab but I was just wanting to know if anyone else had anymore ideas on quieting it. I know the 1100 cab has a very thick insulator between the engine and cab. I think the specs on the dynamat xtreme say it is good to 300° f so the piece under the bed should be fine.