While I agree the classic GT's sound better, the new ones were built to do well in races per current rules, and they are! I saw them take their first class win at Laguna this year and they were much quicker than the older cars they compete against. Granted IMSA's BOP has a lot to do with who is competitive and who is not, but we also saw similar changes to the P class in US and International races in the past 20 years - from 333SP, R&S Mk III, Panoz LMP1, to Audi R8, R10, now the Hybrids, etc. The newer cars sounded like vacuum cleaners compared to the older ones, but they were so fast and efficient and if they win, then the lovely sounds don't really matter much.
Except to the fans who long for the old days, which I think will only be in historic and gentlemen's racing. I do not look forward to the day when there's an entire race of electric cars whooshing around!