My S2 was hanging too low under rear and hitting ground, they took whole sytem off and re-aligned front downpipe, cut extra splits in middle pipe to close up and grip better, put me an additional hanger on rear x member to help keep back box up nice and tight then refitted everything for £40.
My mates S1 was not as bad but he had a 4" tip which he wanted off so they aligned his and replaced the tip with a fresh one about 3" diameter and a bit shorter which looks much better all for £50.
In both cases they did a great job and really took care of the cars.