1999 Kia Sportage exhaust system problems

This kia was purchased new and is a one owner car. It has had 2 master cylinders, and 4 sets of brake pads. The car currently has 50,000 miles on it. The car slides to the right on wet roads and does not stop until it hits something or slows to a stop. I have slid 2 times, rear ended someone the 3rd, and my son hit a light pole. The other times the brakes may or may not work. The problem is worse during rainy weather. The brakes go to the floor and the car does not stop. At times the brakes vibrate.

Exhaust is sucked into the passenger compartment when the rear vinyl window releases from the track that is suppose to keep it secured and closed. The exhaust causes illness and headaches. The design of the window and exhaust pipe do not allow for an exhaust free passenger compartment.