Not a typical tape over diffuser add-on.
This diffuser is a pretty good aftermarket piece but requires more than just some double sided tape and a few screws. Unlike the many other diffusers for the 3IS, it replaces the factory rear valance that is attached to the oem bumper. You'll have to remove the bumper, remove the reflectors, remove the valance, drill your holes for the factory clips and screws to fit on. It looks good once on, but may require some tweaking to fit perfectly. It is not a diffuser that sits over the OEM valance, it replaces it. I bought this thinking it was like the St*llen one but was happy to find out it does not just mount on top of the factory bumper with tape.
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