Which HT leads
 

Hi everyone.
I'm about to change the plugs and HT leads, but would I benefit from getting 10mm leads rather than the standard 7mm ? Also wheres the best place to get these from ? I don't think they have ever been changed, the leads that is. I did do the plugs about 18 months ago but I seem to have a couple of really nasty flat spots when on full boost, its not horrific but its there so thought I'd start with these before booking it in to see if a sensor needs replacing. She's a UK Turbo, mapped to 328bhp at 1.3 boost.. Thanks Julie