Detailing the new '84 80, do I need to T-Cut?
 

Spent Saturday afternoon and Sunday morning cleaning out the inside of the 80, even using a toothbrush on the pipeing to get rid of all evidence of human occupation...

Planning on spending all day Friday cleaning the outside. The car is red, there is no paint fade but it's looking a little "flat". Was going to do the following-

1) Wash (Meg's NXT)

2) Rinse

3) Wash

4) Rinse

5) Dry

6) Clay (Sonus)

7) Polish (Autoglym Super Resin)

8) Wax (Dodo Orange Crush)

9) Wax again

Now I thought this would be good enough, but a friend of mine is insisting that I will need to T-Cut as well. Is this the case?

personally I wouldn't do any cutting unless it was absolutely neccessary. I found that claying did a great job in bringing the paintwork up. It could be the flatness is down to ingrained dirt built up over the years.

I would go through the steps you outlined as a first pass. Then if you weren't happy then consider if a cutting his neccessary. Of course without seeing the paintwork up close and personal it's always going to be difficult to make a recomendation, even against photo's.