Jamboo, a good indication is if you can do 60 - 65 mph in sixth gear and still accelerate when you press the pedal - not fast mind you, but you get acceleration. I caught myself going up a hill the other day in 6th gear at 60 mph, not something I could possibly have done prior to the mod.
Other changes I've noticed:
* I can feel the turbo kick in when I accelerate hard in second/third; although it doesn't last long it's a positive surge of power.
* In sixth at 65 mph I'm getting about 47-50 mpg - it doesn't last long because I'm a bit impatient, but I've tried it a few times and been really surprised.
* Sixth gear/65 mph has much less vibration, especially the mirror - you can now work out whether the car behind is being driven by a male/female B)
As I said on my other post, Lexus GB are well aware of the problem and the solution that Poole have offered (not just to me). Hopefully you'll hear some positive news soon.