seat leon 1.4 tsi

Car is totally dead & being told ECU needs replacing (which is what I came to the conclusion to). Quoted £700. What I can't understand is, google search shows a Seat Leon mk3 ECU for around £50-£100, surely im looking at the wrong thing right? Why is it so much & do you have to recode the ECU...

I opened my doorcard to install symphony ambient lights, however in the process of doing so i have accidently cross threaded the t25 torx bolt that secures the doorcard back onto the door, and now it wont go back in. I have tried searching on Google for this screw but cant seem to find one...

Hello guys I have quite high fuel consumption compared to what i searched on the internet . I´ve changed the air filter (It was filthy) , sparkplugs , fuel filter ,oil and oil filter and i also checked the MAF sensors . All of this did help a bit because the car was neglected in the service...