Hello &

along!
Sounds like a good move you might be making!
Insurance just sucks so I can't see there being too much difference, but when I got mine I was not long 20 year old and the MPS was nearly half compared to Focus ST, Golf GTI/R32, Type R etc...so that helped a lot also!
There isn't a 'buyers guide' that I know of on here, but plenty of threads on what to look out for mate.
Off the top of my head:
Wheels are good at corroding which is covered for 3 years from new, mine and many others have had them replaced!
Smokey turbos, a few people have had this problem...leave the car to idle for 10 mins and if there is white smoke then walk away.
Some people have had problems with noisy/knocking from suspension - lower drop links or sometimes shocks...
BUT you usually only hear the bad things, but the cars are great and have plenty of options!
The mk1 had a wee tweak for 2009-2010 which included darker interior with black plastics and slightly darker wheels compared to the more silver ones on the 2007-2009.
Good luck with the search and hope you find something good