Major service costs and.......

I have contacted a few providers for a major service on my 355. The cost is all over the place and what I should get for my money. Some even paint the block.
What do I really need and how often, everyone tells you a diff. story.
It's the universal Ferrari question from all owners, but a universal answer is a little gray. Sure, Ferrari tells you what they recommend, but I think it's all about the cash. I've seen some cars that go 6-7 years if not a lot of miles are driven. How many years “V” miles and what do real Ferrari owners recommend? My car was done in 2003 with a few thousand miles driven since then. I’ve had the car since 2006 and I’m looking to sell and move up to a 360, but I know every buyer wants the service complete. My question is, do you get the cost of the service back in the selling price or do you lower the price because the service is not done? An $8,000 to $10,000 thousand cost swing in the selling price could be a deterrent for many buyers. HELP. Thanks Guys.