It shouldn't be a big difference. Labor cost are somewhat similar. In the end it all depends on what is done. The 3000 EUR quoted in the ebay link obviously is belts only (but engine is out and you can do what has to be done). The US has similar pricing (at least a couple of years ago): https://www.ferrarichat.com/forum/threads/testarossa-major-service-special.382495/ This thread gives a good overview of what you can swap out if you do more than you have to: https://www.ferrarichat.com/forum/threads/the-real-cost-of-a-512tr-diy-major-service.623216/ Another testimonial: https://www.ferrarichat.com/forum/threads/testarossa-true-cost-of-ownership.555787/ If you're technically inclined and are able to discuss the details of what needs to be done with the shop, the Testarossa maintenance is cheaper that some think. They are not very complex cars after all ....
40 hrs at 200 per hr is 8k. Add min 2k parts and you get 10k. That is a basic but thorough “major” with timed cams. Anything less includes corners being cut. Scope can easily climb from this basic level. Quality work takes time. Shop rates may vary and do not always correlate with skill.
Perhaps “Good” is too general. A quasi-major can be done by dropping the engine and replacing only the belts for a lot less time. Skilled hands willing to cut corners can likely do it comfortably in 12 hrs or so. Even less time if one wants to make it a contest.... perhaps as low as 8 hrs. 12(150)+300=2,100usd. Cheapest shop in town at 150/hr. Only two belts. “Complete” is a better word. The above scenario might be considered good by some people.... but it is far from complete. A skilled tech who takes pride in his work would NEVER agree to do a quasi-major. If you get a lowball quote - run! If you get a more typical quote - proceed with MUCH caution. Romano said it well.