Wow... a lot of advice and a lot of worry and a lot of work! Well done.... but I echo that, all work and no xxxxx... never a good idea, I dont care what anyone says.
A few points, it seems you have not driven an evora or any lotus come to that? so I cant see why the fact that the Emira has less HP than a car you have not driven would worry you, it really shouldnt and you cant read too much into the Evora drivers opinions "yet" as they have not driven the Emira either, apart from Harry and other reviewers, and none of them said it was slower to me recollection... so get that one out of your head. It has 400HP ..ish and thats it and in theory thats enough. In practice, as everyone has said, test drive it and you will know.
Another point, which you slightly raised but is quite evident, most people on here have had or do have several other cars, cars far superior to the Emira, WAY WAY superior, and although they are complaining and xxtching like old women (myself included) they are STILL here. So either they have no life, or they really want this damn car. That should tell you something too.
Finally, every car out there, the same as every country and person out there, comes with good and bad (in my case pretty much all good....yep I really cant think of the bad, maybe the punctuation and length of posts, but even that can be good). Looking at every car is a different experience, the way it makes you feel, whether it makes you want to keep looking at it, turn around and see it again each time you see it, or not. Sitting in every car makes you feel a certain way, comfy, quality, poised, or just plain uncomfortable as too many people are looking at you thinking what a so and so you must be, in my case obviously not the case. Finally, every car makes you feel something when you drive it, again from comfort, to exhilaration in some cases, from fear to back ache in others, but the real feeling you want when you come to the end of the journey, is to not come to the end of that journey! (quite romantic no?)
I agree, you should test drive, but I will also tell you that you should not expect the test drive to make your mind up, a 20 mins drive with a dealer guy next to you, obeying speed limits etc, it will give you an idea, but I have had a few and made decisions based on them, which can often be wrong, but yes you need to do it.
Final point, yes I realise I said finally before this point, there is no perfect car. A ferrari is great, but people generally hate you for driving it, a porsche is fantastic, gt4, 911, but certainly in the UK, you get the same disgust from passers by all the way back from the yuppies of the 80's, keying such cars. You should not look for a car that will give you everything as neither you nor I can give everything to anyone we are with and we can in theory adapt our "suspension, responsiveness, speed etc" more than any car can. However, one of these cars will make you feel a bit more alive from its overall package..... for me, the Emira would "seem" as if it does that more than the others.
Final, final, ultimate point, it doesnt matter! If you get the Emira, or GTS, each of them and I would say Emira more so, it will currently hold its value as all used cars do, especially in the US, so if you dont like it, you sell it and move on as most people on here will do with any car they buy.
Hence, dont stress it.. get it, try it..... love it, great, dont love it, sell it and move onto something else.