Thanks, no problem with water.I even ran thru car wash and checked it and it was dry inside.As you can see I made drip channels between the lid sections.I dont run the truck in the winter ,if you did I could see melting snow and ice possibly causeing moisture problems.It wasn,t too difficult but did take some time.You have to have aluminum welding capabilities and I cut stainless trim rings for around the stacks with the plasma cutter, otherwise just basic fabricating.