with regards to the installation, we do recommend silicon for the installation in order to get a nice flush fitment. also some of the items (diffusers, lips, sides) will require some extra screws (Optional)
removing isn't as easy as removing a double-sided tape, but can be done with little patience and wont cause any damages if removed nicely. we have removed couple of items which was fitted with silicon and no damage to the paint nor the items. and the silicon can be cleaned up with silicon remover.
Plus why are you thinking of removing now!!!! .. install forever
silicon we use is a heavy duty silicon for outdoor items. it comes in black color and its not the one used for glass, its stronger and comes in black color not clear.
note: some of the parts we have added a channel for the silicon or the double-sided tape.