if i'm sticking with 4x6 -- is it worth it to get a plate?

[crashprime]

So, I am putting together a little replacement system for my '94 fullsize chevy ext cab, and I am stuck with 4x6's in the dash unless I go for a $150 set of q-forms (qlogic's kick panel), and I am not really looking to spend that much for the speakers, let alone an enclosure by itself.

My options I've narrowed down pretty much come down to Polk vs Boston Acoustics.

Each brand has a fairly highly regarded 4x6 coax (at least as high as that unfortunate size can command)

So I am looking at the

Boston Acoustic SE75 vs 746
Polk dxi460 vs dxi460p

the difference between each it seems is that one is a 4x6 oval shaped speaker, and the other is a plate containing a 4" round and a tweeter. I don't have any audio shops near me to listen to the difference between the two, but my goal is the loudest and clearest speaker that will be driven off a headunit. It's going to be just the front dash speakers running, as I don't need rear fill in a pickup, and getting access to the rear speakers in the back is a huge pain that will likely result in cracked panels.

I guess my main question is ... will a plate usually sacrifice loudness for quality?

I can only imagine a plate will usually sound better than an oval 4x6.

Then again, is the sound profile of an oval speaker that different when talking sub-$100 coaxials?

Any opinions on those two brands/models of speakers when put up next to each other?

Thanks for any and all opinions guys!

[sbelew]

I can't speak to the Polks but, I have a set of the Boston SL80 6x8 plates in my truck and they sound great. Based on my experience, I would go with the 746.