im 21 and have a lexus is s, its the bottom of the range model but that doesn't matter to me! apart from the rs200 all the uk is200's have the same engine! the s is the bottom of the range, se is middle of range has extra's like sun roof, heated seats etc. and the sport is the top of the range with the full works!
insurance is £930 fully comp for me, with 2 years no clains discount!
im modding my car as well, i started with the bottom of the range so that the insurance is as cheap as possible before the mods go ahead!
at the end of the day no matter what one you buy, your going to be happy!
jason