insurance with category

i was wondering if i get a car of them insurance websites with a category c or d , how will this affect my insurance ? any one know rough number that it will increase on ??

 

do you mean insurance cat or damages etc

 

dont think it makes a difference,if so not much. friend of mine has a bmw 3series thats cat c or d,cant remember its a 2.0 and he only pays 600