It has left the series to ponder what’s best for 2016, and whether following the ACO’s new 2014 prototype regulations is the way to go for its next formula, whether a brand-new Daytona Prototype formula should be created, or if continuing to blend ACO- and GRAND-AM-derived prototypes in a single series should be carried forward.

“I think we made it really clear when we did the announcements on class structure that it was what we wanted to do for a period of time, that was inclusive, but not definitive forever,” said IMSA COO Scot Elkins, who’s overseeing the USCR’s current and future regulations. “When the new prototype regulations come out in 2014 and then, as I'm sitting on these GT convergence meetings as a representative from the United States, when those regulations come together, it seems like everything is shooting towards 2016.

At present, the P2 category, which the USCR will administer through 2015 using the current P2 rules, allows turbocharged engines to along with naturally-aspirated units. And starting next year, turbo engines will make their debut in the DP class as Ford replaces its current 5.0-liter V8 with P2-based 3.5-liter twin-turbo V6s. GRAND-AM also continues to allow the use of OEM-themed bodywork in DP, with Corvette taking the plunge in 2012 and Ford set to join them next year.

GRAND-AM’s DP rules have allowed flat-six engines, along with V6s and V8s up to five liters in capacity, and it’s believed Audi is working towards adapting its GT3-spec V10, which powered the 2013 Rolex 24 At Daytona GT class-winning R8, for DP competition next year.

Despite the existing DP engine regulations, it’s clear that along with Ford’s twin-turbo V6, the USCR is willing to relax its tight limitations on ineligible powerplants like Audi’s 5.0-liter V10.