I have to assume that all of the crossfire doors use the same size speakers which would be a 6.5" component speaker. If you do not have much experience with car audio, this is not something I would suggest doing yourself as there are many little things that need to be taken into consideration while installing the speakers to maximize performance. As for pricing, Sound Advice (company I work for) sells component speakers for up to $5,000 for a pair, but I would not suggest going that high. Get a pair of speakers that closely matches the quality of the rest of the system. You do not want to spend $1,000 on speakers if you are not going to use a high quality amp to power them. Let me know what system you are trying to put together, what you want to emphasize on in the system, and I can help you put one together for your budget, which you need to let me know as well. Also, tell me where you live.