Good Lord. Honestly, and I really mean no disrespect, you need to get a PPI by a top mechanic. A Ferrari mechanic with 328 experience will have forgotten more about 328's than you will know and be able to recognize between now and the time you buy your car and probably ever.
Why? You go through your checklist and what does that show? Will you know if the water pump is going bad? Will you know if the injectors need replacing? Will you know if the plug extenders are going or not? What about the clutch? Shift shaft seal? Will you know where to look to see if the frame was repaired after a wreck? I won't even get into leak down, compression, etc.
There's not much that you will see in your checklist that would be cause for concern. I mean, okay, so you look in the trunk and see that carpet's not quite right in the corner. Well, it's a Ferrari. 25% come from the factory like that. Does that mean that you won't buy the car? So you go drive the car and inspect the engine again. What if you see nothing? Does that mean that the engine is good? Do you know what you're looking for? what are you looking for on the oil pressure gauge? Lots of times, these are way off even in spectacular cars that are real winners.
If the car is ratty, you'll see right away and walk away. If it's a stunner, you'll see that right away, too. What you'll never see is the really important stuff. You need a PPI and expect to pay 5 hours worth of labor on that on a 328.
The point is that your checklist is nothing more than a cursory glance at best. If the car looks good to you and fits within your criteria, just send it off to a trusted mechanic who can tell you what's what. A good PPI will have about several pages plus 50 photos of everything that you described plus all the things that you (and I and everyone else who's not an F mechanic) knows next to nothing about.
Just the facts...