I have a brand new unused genuine Ford base model spoiler (for my base model ) with all the bits & bobs and have been pondering the same thing for some time.

If it gets a load of tiger seal then that's it - it aint budging but the shitty sticky back strips on the underside of the spoiler and those little clips look like someone could have it away if they fancied it.

With that in mind I reckon bonding it on permanently is the way forward - you know you aint gonna lose it parked up somewhere or have it fly off the back of the car whilst driving.

I'm sure Ford knew what they were doing when slapped it on the RS500 but like I say just looking at what came in the box doesn't fill me with confidence