I'll put in my car designer 2 cents.
I won't bash - or try not too. First off, I like both the aero nose and the 4-eye nose but am hugely partial to the 4 eye nose ESPECIALLY on a notch (like mine).
My design opinion - The 85-86 nose is by far one of the cleanest and most agressively styled Mustang front ends ever penned. My new favorite front nose design is now the '07 Shelby GT500 but that's for another discussion.
If you really stare at it and just really look at how "chunk" and muscular it looks you can really appreciate the "look". The the LX Aero nose fronts are clean and OK, but like somebody mentioned, it has no chin and it looks like it's kinda smmiling at you in a nervous way. Now a Saleen or Cobra nose looks good.
As an owner of an 85 and having been in high school when the 85 and 86s were new that's what I've always wanted. Even the LXs have just as much attitude as the GTs only they're sneakier!
It is YOUR car and do what you want but makin' a car something it's not like in this particular case just isn't the way to do it in my opinion. Working with what you have and improving on that - you'll get more respect than just bolting on the areo nose. Take a look at the gray hatchback pic posted a page or 2 back (speeding down the road) - all he did was add a nice splitter - changed the whole look and attitude to the car. It looks faster meaner and gives it a competition look all by adding a simple aluminum splitter.
Another thing I try to tell people - wheels and stance are 50% of the "look" of your ride. Even a freakin' Pinto could look good lowered 2" with a set of 17" HRE wheels and Nitto tires! Well maybe but you see my point(also I wouldn't put a set of HREs on a PINTO! LOL!)
I attached a pic of My 85 Notch. It's getting a full coilover setup with Bilstiens and a set of 18x9s rear and 18x8 front custom made wheels. 4-eye Notchbacks look Nasty in My opinion (but I may be a little biased) I had a 92 5.0 Notch about 4 months ago but I sold it, love my 85 a lot more.
Here's something my automotive design instructor said to a student in class I'll never forget. The student thought their desing looked great but the fact of the matter is it wasn't and it had nothing to do with opinion and they didn't want constructive crititcism so this is what he said...
"A piece of S--T painted purple with yellow polkadots is different but it's still a piece of s--t!" And he said it calmly, and with a smile on his face!
So something can be different but it doesn't make it better or better looking in all cases. Take the time to think about the modifications and if it's money well spent or could it be spent better on something else?
Sorry for the soap box but I needed to get it off my chest. I actually pulled into MPS about 2 months ago and a guy had this bodykit on his 89 Mustang and it is just absolutely horrific looking. Besides, I beleive it's fiberglass and the fit and finish was not good - uneven gaps and you'd have to do a lot of prep work and sanding to get the panels smooth for fiberglass.
Some suggestions:
1 - put an aluminum front splitter on the front - custom shape it to your liking.
2 - Get a Mach 1 front chin spoiler and custom cut to fit. 5.0 Rest did this on an 84 anniversary GT350 ca and it looked great.
3 - Maier Rcaing makes some fiberglass body parts for 4-eye cars.
http://www.maierracing.com/
Good luck,
John