[Akrapovic]

I'm not sure what your point is. IMSA made an attractive class, regardless of where the manufacturers came from.

Using the same metric of retaining manufacturers, Le Mans lost Peugeot, Audi, Porsche and Nissan. You could argue costs were too high, but when it was cheaper we weren't tripping over manufacturers either.

Historical data like that ignores the lack of manufacturers in LMP1/LMP900, on both sides of the pond. Also ignores that DTM is at deaths door with a record low manufacturer entry. So it can be rationalised anyway someone wants, saying "Well what manufacturers ACTUALLY want is this", but recent history disagrees - DPi is the most popular manufacturer based prototype series in the world right now (even if you include GT500).

So theory based on history is great. But practically, DPi is doing great. So if we're going to go down the route of a purchased chassis, some branded drag bodywork, and a balance of performance, then DPi seems just fine. Anything else is overkill - the idea of spending money to build your own car just to have it BoP'd down is particularly silly.

Personally I'd rather see more traditional racing with actual manufacturer cars (with a healthy amount of private cars somewhere in there too). I'd personally make spec hybrid systems to make them more accessible. But if we're going down the route of BoP's a branded drag body work, then I don't see a reason to not use DPi.

Edit: and Chiana is spot on - there's no requirement to run a hybrid as a manufacturer in LMP1 for 2018.