hey guys. did search but found nothing. need to know if anyone has info. on jet hot headers ground clearance. i have 18 inch wheels, and an eibach pro kit lower- my cars air dam never scrapd on speed bumps when i had 245/45/18 tires. recently i got 245/40/18 tires. now it scrapes barely on anytrhing. the differenrce is as minimal as the new lower profile tires. what kind of clearance should i expect? thanx