Ok so yesterday I got a flat tire driver/rear. So now I'm looking to get new tires and I checked and both rear tires need to be replace, the front ones are good for a little while longer. I currently have this:

Nitto NT-555 Extreme ZR 225/45ZR18 on the front and 245/45ZR18 on the back.

This is what they came with when I bought the car from a private party. I use my car as a daily driver. Are these Nitto Extreme any good? I'm thinking about just getting the same ones since thats what it came with but I have no clue about tires. I wanted to see if you guys think getting those again would be fine? Or are there other better options? I'm really not looking into spending a fortune on tires either, just something that handles good rain or shine, i'm in san diego so its mostly summer like conditions year round. I was reading good stuff about the Falken 452 but is that more of a "racing" tire? Lastly I have a friend thats a mechanic for Ford so he's going to be putting in my tires and balancing them for freebies!! So all I gotta do on my end is get the best price I can get. So do you guys recommend keeping the Nitto or going with something different, and if so: which ones? Thanks!!