The vacuumsupply linefor the brake booster doesn't run directly from the TB but it runs from just behind it. The extra airflow might have increase the vacuum slightly to the brake booster which would make your peddle a little more touchy. The only reason for this is because it takesless of an effort from you to apply the same amount of stopping power. The performance of your brakes didn't change from this, it just means that it's easier to make your ABS work.

 

Thanks for the explanation. It makes sense.

 

The potential is there because it is sucking more air into the manifold. The next person that gets a TB should do a vacuum test on the brake boost supply line to see if there is any change. My guess would be maybe 1in./Hg. Not very noticable on a gauge but it will be felt in other areas.