I can't smell it while I'm inside the car but when it's cold and my car has just been started and hasn't warmed up yet, there's a very distinct exhaust smell... It smells almost like fried circutry from an electronic device... It disapears when the car warms up a bit but any idea as to what this is?

 

Head gasket?

 

If it was a headgasket, wouldn't the car always be ready to overheat? I havn't had any heat issues although my fuel milage has dropped to barely 22 - 23 MPG and thats doing 60 MPH on the highway using the cruise control... Also I can actually see the exhaust during a cold start aswell, I mean just plums of exhaust smoke.. ... I'll state again none of this happens when the car is warmed up or even if I crank it while its warm... I'm uncertain as I rarely ever go WOT but the car doesn't seem as stout either, it's certainly not hesitating but from a roll it takes quite a bit of fuel to get it going...

 

What color smoke? White = coolant in cylinder, blue = oil in cylinder (not sure with these new synthetics), black = too much gas. Unless you lose a bunch of coolant, you won't necessarily overheat. Check coolant tank/radiator levels as well as oil. Something's burning!