How are the stock sound system in the EL Ghias? Anything that needs an urgent upgrade, I'll probably get a new headunit for it any other recommendations?

Depending on what your after honestly...
IMHO the stock ghia premium sound is pretty good for a stock unit from a ford of those years; its got many features and in general is very reliable bar a few cd changers putting up the red flag.

If you were going to change anything id guess the "sub" is the weakest link within the system however im not saying its s**t as it does what it was designed to do but once you turn it up a bit its all over.

The rear speakers and front speakers are ok - nothing flash however i found the front tweeters up near the dash of decent quality; comparing to mates stock systems.

I wouldn’t change much unless your willing to install decent amp/head unit and new speakers for front and a little sub. rears are ok for fill unless your after superior quality.

Best bet is to have a play n live with it for a week or so; i think you will be pleasantly surprised for a stock unit.

I wouldnt touch my Fairmont Ghias audio system. I had all intentions of doing so but when I heard how good it was its not worth doing it. If you going to enter audio comps and such then fair enough but as it is its awesome.
I wish I had the brains to put it in my EL XR8.

I'd leave it well alone. Its fantastic.

Aren't there links in this website that let you install the premium sound system into your car?

I have to agree with Daniel & Timmeh here .... the stock sound system on EF/EL's are surprisingly good.

A year ago I replaced the head unit in my XR because the stacker in the boot died.
I only replaced the head unit because for me it was a pain in the a*** to go to the boot to swap CD's around .... I just prefere having it all up front.
But I didn't realise how good it all was until I entered my first audio competition 2 weeks ago.
The judges couldn't believe how good the front stage sounded for just stock factory speakers .... the tweeters in these things are very good.

So as mentioned .... no need to rush out and replace things just yet .... enjoy what you have