What to use and where to buy: advice for attaching plactic thinlip spoiler on E46.

[Bmw.wp]

Hi Fanatics

I bought a thin lip bootspoiler last year and fit it on my car. After a while it came loose and i took it off. Now i wants to put it on again but dont want to use some cheap product.

So please share what did you use and where i can buy it.

Thanks.