I bought my Ark for $1500CAD (~$1100US) when it was on sale. If you're not in rush, I suggest hold off your purchase until it goes on sale. Retail prices are nuts. .
For lowering, the best bet is using megan racing adjustable control arms (front and rear) to make sure misalignment after lowering doesnt eat up your rubber unevenly. And use BC coils. You'll need to readjust the height and dampening a couple months after you install them because parts will sit in an slightly change in adjustment - fine tuning would be recommended.
Body kits, I was never a fan of. But depends on what floats your boat. There are a number of online retailers that offer body kits; plenty in Russia as they love Infiniti! I wouldnt quite recommend getting any parts shipped from Russia, it'll cost a ton plus the workmanship is not necessarily the greatest. With any body kit you will have to do some minor adjusting when installing. Nothing is a perfect exact fit.