no speaker u buy will be a direct bolt on.. u gotta make ur own bracket. or do what Xoxol did with his install http://www.newcelica.org/forums/showthread.php?t=273723. I made my own brackets using some wood that i had lying around and using a drill and a jigsaw to make it. There's also areas u can mount crossovers on there too if ur speakers come with them.I would prefer a direct bolt on
The celica gts premium sound package came with with an amp for the stock deck. the gt did not. As far as having an amplifer for speakers... if your decks powerful enough u wont need one. I honestly can't tell the difference with my deck (jvc kd-avx2) if it's hooked up to an amp or not. It just sounds amazing to me. now for subs, install a amp.infinity kappa perfects make a 6 1/2 component but it won't be a direct bolt in the front doors, you will have to make a bracket to hold it in (i know this because it is what i'm running) but they do sound good for the money if you look around on like ebay or somewhere like that you should be able to find a set pretty cheap, but they aren't going to sound good unless they are amplified and i don't know enough about the stock stereo in the celica to know if they are all amplified or not,
is it well know in Europe? Because here its just starting and the company I work for is the only distributor of Beyma in Northern America.