Listen, I just sold my Mercedes CL600 to get my 2005 NSX. That MB is $140,000 new. Even selling it used, it sold for more than my 05 NSX. The level of luxury and refinement, parts quality and the types of materials used on my MB versus the NSX is night and day. NIGHT AND DAY. The MB sucked its doors shut... my rearview mirror was motorized.. AC and massage in the seats... and a super smooth V12 that pulled like a locomotive... but I have 5X the fun in the NSX. Its all about driving fun in the NSX. How it looks, and it looks great, is just a bonus.
I am sorry, I don't mean this in a bad way... but I can drive 10 minutes and see five M3's. I have seen one other NSX in the past 2 years here. In another year, your M3 will just be the "old" body style. In another year, people will still ask of your NSX "what kinda car is that? Is that a Ferrari? I have never seen one before".
My MB was in the shop A LOT. If that was did not have a warranty, I'd be typing this to you from a homeless shelter. The NSX is solid. 15 years of this car has made it very reliable and it was solid from the start. I don't think you need to worry about a warranty. If you are, you can always buy a warranty but I wouldn't.
You will definitely take a bath on the M3. Thats the shitty part. But I can tell you that you will LOVE an 02+ NSX. And it holds it value waaaaay better than anything else comparable. The NSX for years was Intellichoice's #1 car for lowest cost of ownership.
By the way, 2005 is the last year for this NSX. No such thing as 2006,2007.