[Mustang92]

Go to the track and see for yourself.

Any lowering spring will reduce the amount of weight transfer, that is the purpose of lowering your car to prevent body roll and stiffen up the ride on the street for handling. By doing this it prevents weight from being transfered to the rear on launch at the track regardless if they are progressive rate they are still stiffer than stock so it will hurt your times.

Straight pipes will never add power to your car especially not 15-20HP with a stock H pipe. The stock mufflers on our cars flow near perfect and there is very little to nothing to be gained by changing or eliminating the mufflers other than a little bit of weight loss.

As for the Toyos I don't know personally but fact is I seriously doubt they will hook that much better than any other street tire out there. If so it will be marginally, they will never hook even close to that of a Nitto DR which is barely considered a DR.

Again go to the track and see for yourself. Manufactures will tell you anything if it means getting more sales but fact is they don't have experience at the track. I can't begin to tell you how many people I've meet at the track that get a new stang and get big 17 or 18 wheels with big tires, lower the car and hit the track and complain about how slow the car is or how they roast the tires through 2nd or 3rd. Or even better how some people think a set of upper and lower control arms will make their car hook like a drag car with lowered stiff suspension and street tires.

Bill