Need Stereo Help, new and stumped Options

[TrdKing]

Ok I went and picked up some 6 1/2" speakers for my celica and came home only to find out about the front being 6 3/4" and the backs 5 1/2"?

What do people actually put in for speakers? size? power? brand?

I bought a decent deck and was just looking for some cheap speakers that sound good to go in with the deck.

After looking at the back speakers is there anyway to actually fit an aftermarket speaker in there they seem to mold to the plastic mounting piece. Could I buy a 5 1/2" and put that in their? Will it require any modification?

I read through the front 6 3/4" inch front speaker install and was wondering is that what everyone is doing? Is it that hard? What about the back?

I bought some Performance Teknique speakers for 150 CAD but they are all 6 1/2"
but heard they arent that great. I am going to bring them back and probably get some panasonic speakers to go with the panasonic deck.

Please help me out I dont want to buy crappy stereo stuff and I would prefer something I can put in myself.

[TrdKing]

ok so components are a "seperate" pieces system.

for everybody who has them do you just replace the tweeter with the new one.

also how would you wire everything in to go to an amp