My experience is that Twinman’s advice is exactly correct.

I bashed a Senior Kadet with three engines and am now flying with two engines, well sometimes one. It would be a shame to spend $1,000 plus dollars and six months time on a P-38 only to discover the thrill of a 60 second flight. P-38 is reported to be absolutely the most difficult airplane of all to fly when one engine goes out. Flight experience with an engine out on a more forgiving airframe will be invaluable when you eventually put a P-38 in the air.

Pictures and movies at:
http://engsw.com/Bill/

Bill