Why 2 Ohm Speakers?

for some reason my dodge Dakota has factory speakers @ 2 Ohms.  Someone on my Dakota forum who works for Dodge says they started doing it a coulple of years ago.  Now I can only imagine that they do it to make the stock system louder and "seem better sounding" to the buyer.

Anyway,  I have put in an amp I had lying around (100 x 2).  I amped only the front channel, which I added tweeters in the sail panels to.   The front channel is super loud, I have the gain about 1/32 turn.  going to put a meter on it later today to see total impedance, but the stocks and the tweeters are tied in so a 4 Ohm tweeter and 2 Ohm speaker ...

I also want to tie the rears into the fronts.  I was thinking about hooking up the LF and LR in series to INCREASE impedance (becuase of these 2 Ohm stocks), then doing the same w/ left channel.   I ONLY HAVE A 2 CH. AMP so not many choices.

Any thoughts, given my amp, stock HU, and these ridiculous 2Ohm stock speaekers.

SInce the amp is 4 Ohm x 2 , and I am going to be either over or under by some amount once the front and rear are connected (either parallel or series) can I get away with it? 

Also (sorry about all these questions), I know I will lose fade because of tying in the rears.  someone suggested wiring it to keep the fade and lose the bal.  My question is ... if I do that wont the front be the "left channel", and the rear be the "right channel" ? 

This would make the sound @##$$% no?

Just used the calculator here to figure it out... I THINK,

The front right in parallel 4 Ohm tweeter and 2 Ohm door speaker = 1.3 Ohms

The rear 2 Ohm speaker connected to the front right channel in SERIES = 3.3 Ohms for the right channel,  if I do the same for the Left channel then each channel on my 2 CH. amp would be getting 3.3Ohms.

This should be ok for a 4Ohm amp right?

I agree with stevdart, get rid of the OEM speakers. 

Part of the reason "why" car manufacturers use 2-ohm speakers is to save money.  The average consumer (wrongly) believes that "louder is better" when it comes to car audio.  By using 2-ohm or even 1-ohm speakers, car manufacturers can get away with using lower power, cheaper amplifiers for the same loudness levels as would required 2X the size amps with standard 4-ohm speakers.  It saves them dollars, and car manufacturers will do almost anything to save dollars.  This is also why some people are disapointed when they replace OEM speakers with higher-quality aftermarket speakers but keep the factory HU/amps.  Suddenly the amp has to work twice as hard so perceived volume and bass levels are lower.

Ok... my meter tells me that my OEM are infact 4 ohm (3.7).... maybe these guys were talking about the infinity system, who knows.

I am going to eventually replace all 4 speakers, but this is a budget build (wife let me get the truck so I can't go and spent $1000 on system).

The sound is going to be comprimised anyway because I only have my good 'ol faithful 2 channel amp that I have had for years running my subs in past cars.

got everything hooked up yesterday and it sounds 10x better than stock so I am happy for now.

Next I will sneak in some new speakers, 1 pair at a time hahahhaaaa   she will never know.

Thanx all

build total so far...

Tweeters in sail panels $20, 4 hours

Old amp... 4 hours (long since payed for itself )

Metra harness  $25 (for both HU and OEM harness to go back to stock easily).

Money spent $45

Happiness thus far  Priceless (espesially w/ metalica blasting through cab)