Nope,

Its a fine pitch thread mate.. Can be found on ebay quite cheap.

(mis-read the post - fine pitch thread on the turbo downpipes, not sure about a sport?)

 

when you say its of the downpipe i assume you mean near the bottom? Not familiar with sports but on a turbo its a fine thread i.e UNF and a 14mm socket? hmm, i would say around 1/4 or 5/16 UNF. BUT I am guessing.. so probably your best bet is to take the bolt off the downpipe and take it to a local nut+bolt specialist - danlett or similar and they will identify it for you and supply you with the correct nut.
Your last option (and by far the cheekiest) is to find a supplier who sells the downpipe and ask them what nut it is - They can only say no!!

 

the thread i believe is 10mm fine pitch. Normally a 17 mm socket but the japs like to be different. as long as the thread is 10mm fine the socket size doesnt matter.

 

try searching ebay for; M10 X 1.25mm FINE PITCH