Well I think the Attrage (one available here) is the same model since 2014? I’m not sure about imports and other variances.
Below is the information from tirerack/wheelsize (websites you can check out yourself) Mitsubishi Attrage 2015
– Center Bore: 56.1 mm
– Lug Size: M12 x 1.5
– Trim Production: [2013...2016]
TIRE 175/65R14 ---- RIM 4.5Jx14 ET46 with PCD 4X100
Optional rim (maximum size given?)
TIRE 185/55R15 ---- RIM 5Jx15 ET46 with PCD 4X100
This will give you a general idea of what your STOCK rims are like and what you could replace it with without too much work. I’m guessing 16s would fit but you’d need a thinner/lower profile tire + ensure it doesn’t rub. Are you planning for lowering or upgrading suspension?
For offset you may need spacer or adapters for other types of wheel. Keep this in mind. My advice would be if you can, go to some tire shop and look at your options. Plenty around and they will provide some ideas for your options. You’ve also not mentioned a budget so you can ask them and at least get an idea of what the costs will be like. Good luck!