I'm a previous 03 cobra (663rwhp nitrous car pre ported blower) owner who is 29 as well, hopefully soon to be an owner again.
Honestly, I have never heard your listed negative worded like that as one of the Backdraft negatives. It is more so worded simply as the Backdraft not being quite as close of an exact replica as some others (such as Superformance). My view on this is pretty simple;
The only car that is a close comparison to the Backdraft is the Superformance. With the Superformance, you pay about 20% more for a "better closer to near show quality paint job". The body work and paint on the Superformance IS a bit better than the Backdrafts "near" show quality paint job. So for an extra $10-15k with the Superformance, you get a better paint job (there are also a couple options added in a base Superformance, so lets just say that the Superformance, option to option, is about $10k more for that paint job). You also get a much more accurate replica.
What you don't get is quite as good handling characteristics. The Backdraft, while not quite as accurate of a replica, is the better "performing" car.
As far as rattles/tightness/quality/problems, the Superformance and Backdraft are extremely close. I don't think anyone could be honest with themselves and claim that one is assembled at a higher quality than the other.
The Backdraft wins on performance and price. The Superformance wins on paint/body work quality and original accuracy.
Engine choice is a personal choice. I am of the opinion that IF resale is important, don't consider the Coyote. The overall price might not be effected, but you will limit the buyers market. My little carbed dart block 351w 427/TKO-600 is a nice streetable engine with 480rwhp. I would need the supercharged coyote or a coyote with lots of head/internal work to get that, and the price would be a bit more expensive, though not by much. For a reliable fuel injected engine, the Coyote is extremely tempting in regards to cost. It is NOT a substantially more expensive engine setup.