Yes it is and the NSX continues to be overpriced.
I’d have the Audi strictly because it’s the highest in demand and would be easier to sell when my real racing adventure went broke.
Another thing I should probably mention is that most GT3 cars/ race cars need engine rebuild after a small amount of mileage. In general, that number is smaller for turbo engines and for small engines that are forced to produce a lot of power (like the 4L boxer 6 of Porsche).
Meanwhile, AMG GT3 is using a whopping 6.2L NA V8 so we can imagine the stress on the engine is relatively smaller and in fact, AMG GT3's engine can indeed serve more miles before a rebuild. Therefore if someone really wants to work hard to afford to race in GT3 as a private team, AMG is the go-to option. It is almost as popular as the R8 I believe. There are tons of AMG on the grid IIRC.
Next step is to perform well enough so you can have some sponsors share the burden with you. However, if you work hard for a lot of years it is very difficult to beat those young kids trained by the factory team but hey, we have different classes and you have a pro driver helping you if you are in the pro-am class.
Meanwhile, the NSX's V6 endures much less miles between rebuilds, not to mention its original higher price. If you are a die-hard HONDA fan, I would actually recommend you to buy a HONDA fireblade (CBR1000 RR SP) motorcycle, which is a fraction of a fraction of the price, and is extremely fun
(The new 2020 version is AMAZING)
(And you you adjustable brake balance at any time (control your right hand and foot), "TRUE DRS" (put your head down), and five digits redline RPM, which are definitely better than the GT3 car.
It can kill you but that is OK.)