yup engine in car and running but extractors not fitted as yet, they still need to be cleaned up and sprayed in flame proof paint. As for the benefit, i was told approx 5 hp. They wont go on till i get the exhaust done and then i will get an overall comparison, standard headers and exhaust against aftermaket headers and exhaust. i am going to slightly modify the headers by getting them cut at the y point and getting a larger section welded on to match up with the 2 1/4 system planned