Hey guys, I was looking to buy an STI and found one, wanted some advice on if you all think its a good deal

. It's a 2005 with 60k miles and perfect exterior/interior. Took it to my mechanic and it checks out, care is well kept and is flawless he said. The guy is asking 15.5k.
Now before I run to my credit union and take out a loan, I was wondering if the cost of maintaining/repairing this car is a lot ( I currently drive a 1990 300zx and figured it can't be much more than that hehe).
Any advice is greatly appreciated!