Is it possible to put a 2.5L V6 KL engine from say a 626/Millenia/Mx-6 into a 2003 Protege LX?

 

you should be able to fit it but the computer would have to come with it and possibly the transaxle. the main question that i have in this situation though is why? an inline four is going to get better torque and more horsepower per liter. you will get more overall horsepower and torque out of the v6 but there is also the weight of the motor to consider and the fact that your mpg's will go down. i recommend the 2.0L inline four from that year.

 

But can it be done? are the mounts in the same location as those of the 2.0L protege motor?

 

i'm not sure but mounts are the least of your worries. you can always customize mounts.