My vote goes to install as well....probly the mids are warping screwedi nto a less than level baffle...unless you're playing the deck with all the loudness, low, and bass up to max, with the HPF off.

 

What could be wrong with the install that will cause the mids to blow?

 

If the mids are not attached to a level surface, it warps the basket, distorts the cone shape and causes the voice coils to rub. End result, blown speaker. If the surround is making contact with the backside of the doorpanel, same results.

 

The baffles are custom made out of 3/4 inch MDF board. How would I know if it is not level? Would I have to physically take a level to it?

 

Amp them....you can never have enough power!

 

I'd recommend a sub, and leave deck power to the comps.
Chances are that the components are being over driven, to get " 'mo better bass". And it takes power and lots of air in motion to get bass.
If you still blow them after that, then yeah, get another amp for them.
But the real cure IMO is a high powered sub, an amp for the comps, without sub will be a band-aid.