Ok, sure. So you believe the Red Bulls were the completely new way of generating sounds he spoke about? But they can't manage that for more cars, yet?
Effectively, yes. There has to be a reason all the Red Bull cars seem to have the exact same exhaust pipe on them.
My thinking, as soon as the Junior was unveiled, was that they are making up for missing sources. Those missing sources can't just be added to the game in the same way the current ones are, because there's only so many concurrent sounds you can have. Something has to give, ideally you'd swap sources in and out as and when they are prominent and then "not important" any more - there are many ways to achieve such "virtual" channel schemes, and they need to be both robustly programmed and non-jarring in their aesthetic effect.
There is one key difference in the way GT6 handles camera transitions in replays over GT5 that gives the impression that virtual channels are already partially implemented (GT6 briefly plays the same sounds from two positions in space, GT5 kept the old listener location briefly). Then you have to consider all the streaming / dropout issues everyone is having, and what I said about the fiddly nature of scheduling on the SPUs.
GT has historically only really had exhaust sounds. Exhaust sounds on their own do not do the cars justice, as we know from every GT game, and from the example set by other games. The Red Bull cars, therefore, are exaggerated (I made a video demonstrating it a while back) to compensate, since they still only have exhaust sounds also. I believe I was able to recreate the particular way they have been exaggerated, also (in terms of physical descriptions of the bits that make sounds, translated to my own "model").
So no, the technique used on the Red Bulls (exaggeration) is not transferable to the other cars, the sounds for which will have been authored (mostly already) using the full scheme (all sources) as a target (if only for PS4). Hence also why the Red Bulls all use the same over-the-top, long, resonant, raspy exhaust pipe, as a placeholder (which is why it wouldn't be applied to the 97T, in my opinion - it'll get new samples like the Hudson did.)
There is potentially an element of wishful thinking; I dearly hope that PD plan to include intake sounds as a minimum in their complete new method. That may not happen (esp. on PS3), but it must for their new method, as I've interpreted it, to work properly / convincingly. The facts remain, though: the Red Bull cars really do have a DSP-style exhaust "effect" that is distinct from samples (which they also have assigned to them, in the Data Logger), and that really is "completely new". I'm hoping "illicit behaviour" can offer something more conclusive, but that's for the real experts to share.
By the way, what I was saying, way back when, that the only way PD could improve the sounds would be to use a new method, one that doesn't use as much RAM per source, but exchanges that for processing power, correlates well with what I hear (techniques-wise) in the Red Bull X cars. But it's impossible to know the exact "exchange" they've gone for (although it is possible to know what the per-car RAM budget is for sound, in terms of limits, thanks to the updates). What you save by binning samples, you can spend on "buffers" - i.e. more sources...
Sorry for the long post, but it's hard to succinctly justify such nested "logic"!