ok.. if your looking for power and you want to do some head work and bore out the pistons stuff like that , then having the motor rebuilt would be the way to do it because someone can make those changes while rebuilding the block.. but that costs money and isn't cheap.. now the remanufactured engine depending on who you get it from is more or less the same thing but they remanufacture it to the factory specs, meaning it's going to be the same power as it did when the car was running with a factory motor , but they do give some type of warranty which is a good thing, check out jasper engines, a bit pricey but there solid motors.. it's simple there is more of a chance of internal engine failure from human error when rebuilding, and less when remanufacturing because allot is done with machines and to be honest i would go with the remanufactured motor , just because the company does it all day every day, verses someone manually rebuilding a motor from time to time... but the question is are you just looking to get your car running as it should or are you looking to juice up your car to make it faster.. i just hope there is a reason you have to replace the motor , and your just not trying to make it faster. also depending on what kind of car , you can always just swap a bigger motor in the car which will give you more power..

ok.. when you buy a car the factory gives you some type of warranty.. the free one.. now the dealer is trying to sell you an extended warranty or service contract, but you have to be careful and make sure you read the contracts carefully.. for example are they selling you a manufactures extended warranty or are they selling you a after market contract from some random company. make sure you find that out.. the after market contracts are crap, if you by anything make sure it's from the manufacture period.. now you also have different deductibles involved as well.. meaning it's cheaper to have a contract with a 500 deductible then say a 0 deductible.. also remember it's like insurance it's only good when you need it, and it doesn't cover oil changes , coolant services , brakes, tires, trans service, tune ups, etc.. now if you don't take care of the car and slack on oil changes, coolant flushes, transmission service and something happens and you don't have receipts that you did do the required services at the required times, you are screwed, they will not cover the repair due to lack of maintaining the car.. to make a long story short.. the chances of you holding on to the car for that long for you to need a warranty is slim, most people change cars with in 4 years.. now if you are sure your going to keep the car as if it was the last car your ever going to own then buy the life time warranty( but remember even that expires sometime) and is not transferable to another person if you sell the car or give it to a family memeber.. other then that save your money in the bank and collect interest on it and if something goes wrong with the car it will most likely cost you less then the 3k it was to buy the contract.. also there are many car manufactures that offer a 100k warranties as well as life time power train warranties for free when you purchase the car.. so really do your research and look a bit into the future to see what is right for you.. just don't let the finance sales man pressure you into buying stuff you don't need because remember thats what they get paid to do... the don't care about your interest, they care about there commission...