I would not see why 15x7 would not fit, but I have no clue about he offset. Offset can be tricky, why 185x60? with a 7" wide rim you could fit a 195/55/15 and still be close to the same outer diameter so the speedo would be right ausmming your car calls for 185/60/15.
Probably be cheaper to buy local, no shipping and what not. 195/55/15 vs 185/60/15 is a trade off. You would gain better traction, and the car would accelerate a smidge faster. The down side being a smidge less MPG and a harsher ride form the shorter side walls. Corning ability is changed too, you will not be able to turn as sharp but you can lay into the turn a lot harder before traction is lost. This is of course assuming your comparing the exact same tires with the only difference being the size. I'd find a local shop and see what they say, but if its was me and the car is daily diver go for 185/60/15. If its a fun car id go for 195/55/15
I think the stock offset is around 42 to 45 mm. Not much in the way of 15 tires for this car...I am going to 205-45 or 205 50 -16 where there are all sorts of tire choices. The wheels off a Mazda Miata are supposed to be a direct fit for our cars... 4x100, same center hole size , 16 x 6.5. I'll be finding out soon for sure.