My buddy has a 92 toyota MR2 that has 6.5"s in the doors, and 5.25"s for the 2 rear speakers which I believe are near or close to the head rest of both driver and passenger seats. There are also tweeters on the inside of the door mirrors. This is all stock and he wants to replace everthing with a nice set of speakers.

First, what speakers and tweeters would you recomend? I was thinking Boston Accoutics maybe.

Second, would it be better to buy a more expensive pair of front or rear speakers. At first I was thinking for him to get a more expensive pair for the rear to get better sound and a bigger thump, but if its near the headrests, i dont know if that loudness and thumpyness would be too much for the ears so then I was thinking maybe more expensive front speakers.

I'll take any suggestions I can get

 

Skip the rears and the extra tweeters completely, and spend the extra money on a great set of components. Install them correctly in a kick panel or door pod, strategically aimed at the listener. And then amplify them properly. With a suitable subwoofer system, nothing else is needed to give quality sound.