i would recommend you not to use that mechanic ever again! i would get him to pay for it to be repaired by another garage and threaten him about naming and shaming
to reset ecu connect he green and black connectors under the steering wheel ............well thats wat you do on a my99 then go for a drive until the check engine light comes on and it should be flashing on off at reguarly intervals if its flashing at weird intervals then its a ecu fault code jot them down and check on scoobynet to wat they mean
yep ive notice i have a bit more power at higher revs! also got me shell v max card aswel, wait a couple more miles and the ecu should have learnt the new fuel
omg you didnt let tony at your car did you? lol..........nice job..............make sure the inside of the pipes are washed with brake cleaner or some other alchol
i would check the hoses to make sure there isnt a leak, becuase under normal idle the hoses wont expand but with some boost the hoses could expand and there could be a slight hole or crack on the hoses, get a boost gauge and tell us a reading
i did my downpipe by myself and i recommend you either get a person to help you or get a proper mechanic to do it because its is a rite pain in the arse! took me 6 hours to change the downpipe, but it was in the wet in 3 inchs of rain water and it was dark and i was by myself! if i had more money i would get somone else to do it!
good luck mate! its worth it in the end!