It is my understanding that the seal grease and RPV mod are intended to reduce the piston retraction and thereby reduce pedal travel to engagement. This is not the issue I am trying address. The issue I am trying to address is one where the pedal will stink to the floorboard if you press on the pedal very firmly for a long time. It is my belief that the pressure on the pedal to press it to the floorboard is less than it should be. Again, seal grease and RPV will not address this issue.
Just for discussion, were I to put on the seal grease and install RPVs, the engagement point would be nearly instantaneous, and the outer front pads would drag on the rotor more than they already do. The engagement point would be too high for easy heel-and-toe.
I am trying to understand where the compliance is that is allowing me to press the pedal to the floor. One cause may be air is still in the system. I think I have tried everything to eliminate that as a cause. Another potential cause is fluid leakage past the MC seals. I have performed bleed down tests in accordance with VW factory manuals. The results of those tests did not indicate loss of pressure, so I think I can eliminate a defective MC or fluid leaks. No leaks have been observed. There could be something associated with the ABS. However, I don't have a good enough understanding of the details of the VW system design to be able to identify an element that could be the cause of the problem.
Your outer pad is already dragging? That should not happen, are you sure?
What you are describing (sitting and standing on the brake pedal and it slowly sinks) that happens to all, even with the stock caliper. It has to do with the two step MC and the ECU power assist causing a huge increase in pressure vs pedal effort. I can't say for sure with your calipers, but I can say for certain with the Macan/Q5 caliper those mods do prevent this from happening. I explain why in the post (with a diagram). There is nothing dubious about using RPV's, they have been used in countless street and track applications for decades.
There is no other larger MC options for this car, and other than going to a different caliper (like the ST40), there does not appear to be any other way to improve it. As the original guinea pig now with thousands of hard street and track miles, it works and is perfectly safe.
The only thing I am butt hurt about is the fact that no one mentioned the brake pedal issue before I spent the time and money to upgrade to these calipers. The issue was very apparent from my first test drive, then I find that everyone noticed it but did not want to talk about it (why I still don't understand), but great thanks.
The stock system has a lot of intentional slop in it because VW is using the ECU to actuate the brakes for you. If you don't like that because it makes it difficult to modulate the brakes under track conditions you can turn off some of the ECU assist, but then you are left with a lot of unnecessary and unwanted pedal slop.
The modifications I did go a long way towards fixing that slop, and it has to do with the two step MC I show and talk about in my post. I did this to fix this issue for myself, and I did. You post telling us you are having the same issue and I am just trying to help. I would not describe myself as "butt hurt" just perplexed when I am the only one here who admits to having the same issue and has found a working solution.
You can learn to live with it (apparently that is what most have decided to do), or try my recommendation, or get a different caliper. The only one that reportedly does not suffer from this same issue is the ST40, and I believe it is because they have a significantly smaller piston displacement (almost 25% smaller). I bet that also keeps the MC in stage one, that combined with the smaller MC/caliper ratio I am sure give a very high and firm brake pedal. If I was going to spend $3-4K on a brake upgrade, that is the one I would get.
This is supposed to be just for fun, and arguing with arm chair engineers is not my idea of fun, so good luck.