It would appear that any changes made to a vehicle after it rolls off the assembly line will affect your insurance. Any modification work carried out - i.e a recall - must be done by the dealership.
I owned a 1998 4 litre Jeep. That model was subject to a recall because in the event of it receiving a rear end shunt it was liable to burst into flames .. ruptured fuel tank and all that .. The recall was to have a towbar fitted ..
On the other side of the coin, many, many years ago a friend of mine had his car stolen. The insurance company vastly reduced his payout simply because he'd had new alloys fitted along with a boot spoiler.
And on a different coin ..
Many many many years ago I used to play around with 3500cc Rover V8s. So did my friend, who rebored his engine to 4 litre, fitted super-dooper exhaust manifolds and air filter, along with a high performance camshaft. When he finished the work he took it for a test run (30mph area).
In court the police said that the car had landed 10 feet from the brow of a hump-backed bridge before careering down the road, clipping a lamp post, before careering even further down the road and ending upside down on a roundabout opposite a police station (so he didn't have far to walk to report the accident..).
Unsurprisingly, his insurance didn't pay out because of the modifications. Following the court case they put his premium up .. It's a good job he hadn't fitted a sunroof and go-faster stripes to his car ..