Sticking Tweeter holder, made of acrylic and flat contact.
But car panel is textured and plastic type.
Tried various double side tape, generic and 3M brand wont work.
Using the china clear washable now, it holds a while but may peel in hot weather under sun.

please recommend, any special 3m type?

tried 3M outdoor (red), bought from ori 3M seller, such as lazmall/shopee mall that guarantees genuine products?

if still can't work, there's an even stronger 3M permanent mounting tape that may potentially damage mounting surfaces due to the strength of the glue, they do not recommend that if you absolutely cannot deal with potential damage lol.

Use blue tack, now in many colors.
Otherwise there's the china type transparent silicon double side tape with red sticker cover (non washable) from hardware shop. You wont find it in ace, have to be hardware shop.. in ace only got gorilla brand. I guess it works too but expensive.
Looks like this

https://s.lazada.com.my/s.4qYeT

I am using this type Nano. Red lining better?




I put in cart the 3M original clear and outdoor also.

I am sticking the tweeter holder on the doorpanel, A pillar side so it will be direct exposed to sun by the window.
too much work if i need to line tweeter/mid/crossover to dash front.

Looks like the same one. Unless yours is the washable kind . The non washable is stronger.
But since you stick st the aide (versus a tweeter holder that sits on the dash), its very hard bro
Time to mod your A pillar.
Sorry not much help. Maybe Gorilla tape?