Ford Repair: 2000 Ford Excursion, brake pads and rotors, ford excursion

Question
I have two questions for a 2000 Ford Excursion with V-10 gas engine and automatic transmission.
ONE
I changed my brake pads and rotors at 70K miles. Both the old pads and rotors were only worn about half way. I never have had great braking and always thought it was the vehicles weight. Am I not getting enough pressure to the calipers from the master cylinder? Can I replace with a bigger master cylinder for better pressure? Will SS brake lines help?

Two
Can you tell me where the outside air is drawn into the cabin on this vehicle? The air only recirculates on max A/C. On all other settings it sucks in exhaust fumes from other cars. I would like to find a way to filter the outside air to eliminate this problem which is pretty severe.

Thanks

Answer
Hello and thanks for the question...I'll try to help.
 As far as I know----the brakes on the vehicle can't be altered. Also, stainless steel brake lines won't help as far as pressure goes.
 The intake air should be coming from the air duct under the vents near the wiper blades on the front windshield.
Hope this helps,
Erik