16cm in back or 17 and shave the speaker frame with a Dremel, 17cm in the front with Vauxhall adapters. Think the fronts are quite small unless you use adapters, unsure on size though. Take the door card off and measure them
Hairdryer mate, once sticker is off, alcohol wipes or white spirit to get glue off and then car shampoo, you might have to blend the paint with some light compound afterwards if you can see where the sticker was. I would buy Genuine personally
I wouldn‘t use tegiwank again either, I ordered a mishimoto rad saying in stock and it took ages to come. The forum discount is poor and they never have attractive deals