Courtney, you have told us that you had been advised that the engine needed to be rebuilt, but you have not described your problems at any length, just that you had quite a bit smoke when you floored it. If that is your only problem, you might not need a rebuild. My 560SL did that and it drank quite a bit of oil too. New oils seals fixed all that. I am quite conservative when it is time to do radical things and since yoy are talking big time $$$ I would be even more so. Oils seals can be replaced without pulling the heads. You will find lots of posts on how to do it, much better that I can explain. The seals are cheap and you need only one special tool (can't remember the name). The procedure is time consuming - you have to do 16 valves - and may be painful if you are an old fart like me. If you are young it is a lot less so. While at it, change oil tubes -very inexpensive too. I would suggest that you describe your problem in detail here and ask. The people in this forum have done it all and will tell you if you indeed need a rebuild. My $0.02.

J