Phil H said:I've used rain x but i find that the effect doesn't last long. Now I treat any new car I buy tohttp://www.cleanyourcar.co.uk/engin...ants/gtechniq-glass-sealant-kit/prod_911.html it claims to last 20,000 miles and in my experience it achieves pretty close to that.
I use Gtechniq's G5, better water repellence but doesn't last as long (still lasts up to 6 months!).
https://gtechniq.com/products/auto/...water-repellent-coating-for-glass-and-perspex
