NikaL

I already posted this on audio/electronics forum
I know nothing about audio and car electronics. I'm just a performance junkie. I thought Bose was good system, but the other day I sat in my bodies car and it opened my eyes. He spent over 10G's. I don't expect to spend that much, but want to improve my car's spind quality. I want to change my spreakers, woofer and tweeters. But I don't want anything too big or anithing that will need custom job. I'm just looking to replace with the same size equipment which will fit perfectly.
I did some search and got even more confused.
Please show me some light and give me some suggestions.
Thanks
Nik