I just payed $200 each for 215/45/17 FK 452's which are fitted to my Legacy GT, i totally recommend them. Far better than the 329's they replaced.
Not sure what 18's cost and can't give you a comment on wear yet as they are nearly new.
I also have the FK452's on my Skyline, i find them better than the Bridgestone RE01 i had fitted previously, although they were 17's and my new ones are 19's.........
for Falken FK452's