I touched on this in your other post. A stock or mostly stock 2005 WRX doesn't have the power that warrants much wider tires. Going wider would just add rolling resistance and put extra stress on the drive train that wouldn't lead to better grip or better performance. Back in the RWD days going wider meant more grip but we drive AWD cars and they put down the power across all 4 tires ( 2 if you want to get technical with diffs ). Stick close to stock width of 215, If you get some 225s for a steal then those would be fine but i wouldn't go looking for 265s cause your just wasting money and hurting performance.
As far as wheels are concerned your wheel selection should match your use case. Your stock wheels will hold up to just about any abuse you could throw at them and because they are a bit smaller they will give you more sidewall to absorb some of the bumps during your daily drive. Your stockers are 16 inch wheels and you could get away with 17s without too much of a difference in feeling but I wouldnt go any larger than that on a stock suspension setup. That and your stock offset is 55, dont deviate more than 10mm in either direction and your suspension will thank you.
Some of my favorite wheels are the 05 STi wheels, 17x8 +53 i think and they came warpped in 225s. If you can find a set of take offs those would be perfect for your new WRX.
Slow is Smooth > Smooth is Fast