Insurance Increase With Stage 1 Map

Now I know it varies for indivual circumstances, age, location, no claims, job etc but I'm looking to see roughly what sort of increase people have paid in their premiums so they can run a stage 1 map. My current ins. company won't insure me with a map so will be getting quotes from the guys on here and using various comparison sites but I'm also intruiged as to what people have said in terms of a power increase. Using the comparison sites, if you select the option that says 26+% increase in power, then the quotes seem mighty high ;-)