Stealth / 3000 GT Door Speaker Problems.

(PS I own a stealth) Alright, I ripped my door pannels off and everything, kicked the old speakers, bought brand new door speakers. The stock door speakers were a 6" but the new ones i bought were a 6.5" which i thought would still fit, but I guess I cant measure for anything. But the plastic piece that was screwed into the door, that the speaker screwed into, its too small for my new speakers.. And the only thing that I thought of was to put a piece of metal behind the plastic piece, and have the speaker there magneticly but i dont know if that would be good. I was just wondering if anyone changed there door speaker to a bigger size, and how they did it or if someone at all can help. Thank you.

Not a good idea chief, unless you are willing to saw off a new hole and drill new holes! and dont trust to "magnetically" hold anything, if it is not bolted down then it wont work.