I recently bought a 2013 G37 Journey sedan with 12k miles on it.

Goal: I need a good handling car with descent looks and good sound.

Mods (Considering): Eibach Pro kit, Sways bars front and back, strut bar, 20 inch wheels and Top Speed Pro Y Pipe back exhaust.

Questions:
1) What are the possible mechanical/suspension/alignment related issues I can come across with these mods beside ride quality?
2) What other parts I may need beside the ones I listed in order to achieve this goal.
3) If I go with 20's, then what are the idiol specs I should look for. Like how wide, what offset, which brands from quality prospective..?
4) Is it possible to say within OEM spec alignment with all these mods?
5) Top Speed Y Pipe back exhaust, any reviews?

(Consider me as newbie. I don't know ****, believe me.. )