Is that a GTE?
It is purposely made to ride higher than a GTi.
Ah didn’t know that - that’s interesting.
What’s the insurance implication of lowering… minimal?
I expect insurance implications will vary between insurance companies. Lowering a car though is hardly an unusual thing to do these days, so it shouldn't be too hard to find an insurance company that can help.
I'd be more concerned by the points Exonian raises. The GTE is a heavier car than a GTi, so you'd need to ensure whatever springs you are considering fitting are
a) stiff enough to counteract the additional weight. Shorter springs would need to be stiffer to prevent the additional weight from bottoming the car out over larger bumps.
b) not so stiff or low that they result in an uncomfortable or fidgety ride, or pose a risk of damage to any equipment facing out from the underside of the car.