The issue you have with places like Greenlight is that the insurers they work with want history of you driving similar powered cars, I had a Clio R27 before moving to my Megane 275 and there were no issues when it came to insuring. (I'm 27 for reference)
My brother who's in his late 30's enquired about a 300bhp Fiesta ST with Greenlight a couple of weeks ago and they wouldn't insure him because his current car was an Audi A4 Avant, even though his previous car was a Golf R.
They say that people usually go in stages for example: Year 1 ownership - Clio 197, Year 2 Ownership - Clio 197 Remapped, Year 3 Ownership - Meg conversion 197 etc etc
They recommended Adrian Flux who came back at a reasonable price.
I bought my Clio R27 (Standard engine) when I was 20 and the insurance wasn't too bad tbh, I think the issues might start when you look at meg converted ones.