That is a great analogy, Julian73, because even with just the K&N replacement panel filter, the noise that comes out of that driver's side intake is ridiculous!
I've now done over 300 miles with the 435 flash. Even on a 95 degree day, it is noticeably faster than before and has zero drivability issues - throttle response is a little more direct feeling without being jumpy like some tunes I have run on other cars. In fact, between the K&N, the GRP 3rd cat delete, and the reflash, heel and toe-ing is just about perfect (it got better and better with each modification). No more fluffiness when blipping the gas at all, it just revs exactly like you wanted it to.
Have I mentioned how much I love this car???