used the fishing line approach, you have to pull hard, I ended up popping out the honeycomb mesh with each side but it went back in just fine.
after install i do not think the gills are quite as secure as the stock were ones but they have the look I was going for.
Ordered 8/9/14 15 YMB f80 m3 6mt - week 36 prod
Current: 13 Audi s4
Past: 09 SSII e90 m3 6mt, 07 e90 328i