Too Long; Didn't read version:
Do whatever you want to do with the car but be wary to take some flak from anyone who tries to call you out on putting a body kit on your car without pushing the vehicle's performance limits.
Lengthy Version:
I cannot comment on how the fitment is in real-life and the fact is both kits are high quality. What you're asking is, however, not the quality of the body kits but the perceived response from other car enthusiasts and people in general.
It's my personal belief that you should pursue anything (in the automotive world) that makes you happy. If that means having a bone stock Civic and putting a 16" GT wing on it.... by all means do it. Don't worry about what other people think as long as you truly love what you're doing.
My other personal belief is that those body kits have no real weight in positively altering the performance of the vehicle. Now whether or not the Amuse wing provides sufficient down force to actually benefit the vehicle's performance is not really important. What's important (to me) is can you justify the body kit? Even a bolt-on* 370z, in my personal opinion, cannot justify having an amuse or zele or anything body kit wise.
Now I have no quarrels with even a stock 370z have some SIMPLE body modifications like a low-profile spoiler (like a cf version of the stock, etc) or a front lip. However, when you've put more into the body kit than making the car fast, I just have trouble taking you seriously. I know I'm getting some funny looks and how someone may consider me arrogant, ignorant, or "elitist", that's fine. I just can't justify modifying the way a car looks so significantly (especially since the car already looks fantastic, all it needs is a front lip to square out the front end) without at least getting a few bolt-ons or going forced induction with supporting mods. I just don't see the point in trying to make a car that already looks great, look so different. If you didn't like the way the car looked why didn't you just buy something else? But at this point I have completely digressed and possibly trod on my own personal belief that you should pursue whatever makes you happy, regardless of what other people think.
*Footnote:Lightly modified meaning exhaust/intake/tune/geared. anything that doesn't alter the internals of the engine. bolt-on DOES NOT include power adders; regardless of whether or not you believe nitrous/sc/turbo's are bolt-ons... no one considers those a part of a car with "bolt-ons".