order 2.5" vband kit (flanges and clamp) plus a section of pipe from summit and take them to an exhaust shop.
Vband -
http://www.summitracing.com/parts/sum-694250/overview/
Pipe -
http://www.summitracing.com/parts/sum-621008/overview/
Not sure about your area, but where i am from, all the road courses have a noise limit, depending on the rest of you exhaust setup you might want to find out where the noise level check points are and lift as you pass them..