Shopped around online and bought myself an APR smaller pulley during the Black Friday weekend with a pretty good 20% off.
Took me about 80 minutes to install this weekend, had to wait an hour to bake the new pulley, the real removal+installation is only 15 minutes since our engine bay was designed with w12 in mind, there's ample space to work compared to an Audi S4, you can skip a lot of steps on APR's manual.
I can confirm Racechip does not bleed the extra boost, at least not all. I'm seeing 12.x psi of boost compared to 11.x psi stock @ 5k rpm. Roughly 1.2 to 1.4 psi gain.
I think it's now somewhere between 460-500 HP total output. (funny to think it might be as powerful as some v8 SUVs but double the mpg) Actually majority of the power still comes from the chip keeping the bypass valve closed at high rpm.
For reliability, this Eaton 1320 TVS is capable of delivering 17 psi before spinning itself into parts. I will do some logging with VCDS to keep an eye on miss fire, but for the limited 50 mile after swap, didn't feel anything strange.
I will do some 0-60 runs in the spring, I'm simply too cheap to punish my Blizzaks. Standing start is not the best thing hauling around these mass, it actually shines the most from 35 and up, it can get in triple digits in a blink of an eye!