Lovely build Hurdy...very envious!!
I rang Awesome last week....they done an APR stage 3 kit on a Golf R manual car I believe. I was interested in this GTX kit only if going 4WD as the ED 30 just wouldn't cope with traction. The fitted price was £12k but that was because it needed fuel pump exhaust etc etc. I thought that was a bit steep because that was without brakes, intercooler, suspension, clutch pack and labour, so you'll need to factor in another at least 6k if not more. That's a whopping 18-20k investment on the stock price of the car. A huge grin factor but I could't stomach that investment especially at resell time.
I'd like to do what you have done perhaps buying a cheaper older S3 but knowing how well you can get the Ed30 to track ready status with the right bit's ultimately you are limited to traction even with a dif but it is a cheaper option even running track rubber.recently.
Another option I had been considering was buying an B8 S4 and going stage 2 with a big brake kit. MRC tell me that 500bhp is achievable on a drive in drive out £1500 investment and a £2500-3k brake kit.....seems like a cheaper option. They didn't mention clutch prices or suspension if need!
Looking forward to your vids as and when you get them done!