I used a 3M double tape to put the spoiler on, but it come off lose again. I see that the best way to put it on is to glue. but I can not justify to spend $48 for glue. do you know any substitute for Betalink or any other place to buy it cheaper or maybe someone has leftover. and how much do you think I have to pay to the shop to install it.
Thanks

 

I decided to use $3 epoxy to glue spoiler permanently rather to spend $50 for BMW glue or pay $80 to install it to the shop. I sanded the back side of the spoiler a lot, cleaned it with thinner same with the trunk. Applied the e proxy on the spoiler and used lots of tape to secure it. I filled the gaps with the black silicone. I think it is come out nice.

 

Here is the right photo

 

thats nice man, where did you get it at ?

 

Thanks, I bought it local from Craigslist for $90 and paid $85 for painting it.

 

I have the same spoiler. It came with "3M" tape already but it started to come off after a couple months. I bought some 3M VHB tape off ebay and scraped off the old stuff from the spoiler. Thing is solid now and hasn't started to peel