Rather than tell you what to do, I will tell you what I have and my thoughts on it. Then you can make your own decisions. If you have questions, feel free to ask and welcome!
I have the takeda short ram intake and I made my own exhaust, which I will be redoing because apparently the mufflers I bought were crap (in Illinois they are rusting due to salt). Anyway, both of those made me really happy. I have eibach's as well. Those were nice just wish they were a tad lower, but great ride. Tinted my windows also, some people might not view that as a mod but I like it and was totally worth it to me. I also have the Nismo rear spoiler. Don't see too many of them around. But its nice and differentiates me from the countless other Altimas. I have a set of 18" rims I haven't even put on yet. But they are the stock 18" from the altima coupe SR. But I love all the mods I have done so far. I added foglamps too. I would focus more on the suspension and wheels, but that's me. Good luck!