I'm thinking of replacing my tired (200k+) 4.3L "W" engine in my 2000 Blazer with a low mileage 4.3 "W" form a 1999 Blazer. Is there anything I should worry about like changes in the ECU or sensors throwing up codes or the crank/cam snesors not matching? I'm told by one of my mechanic friends that it won't be a plug-n-play kind of deal and that I really need to find a "W" from another 2000 to use as a replacement. Both engines have EGR's (as GM deleted it in 2002 I believe). Both are "W's". Either way...I intend to swap out the intakes and use my existing intake and sensors. Also I do have the ECU from the 1999 if I end up needing to use that. Anybody have any words of wisdom for me?