Anyone compared good 4" to good 5" or 6" spkrs in the front?

[wdb]

I've got an 86.5 supra and I'm thinking about putting 5.25" or 6.5" speakers in the doors. My speakers in front right now are completely blown and I have no idea what some really good 4" speakers would sound like, especially in those original pods.

Obviously, 5 or 6's will sound better than 4's but the reason I'm wondering if it will be worth it is because that sealed pod might help lend some acoustical dynamics to the sound. Furthermore, the hole in the metal opening is only 4" anyway and I'm not sure how well the sound from the extra size in the speakers will travel through that door panel being eclipsed by the metal and the rest of the panel. I'll also be using the installation method where you take out the stock pod completely and install the speakers on a piece of wood as demonstrated here: http://gallery.sanitylapse.com/v/sup...stall+1-21-06/

Has anyone compared both 4"ers and some larger ones where both speakers were of equal quality? I'm thinking about some 4" infinity reference series 4022is, which have pretty good lows for a small speaker. I don't know whether or not I'm going to run a sub either but my main question is about the size difference. Thanks.