Yes, on this great site:
http://www.alfaowner.com/Forum/alfa-...ers-guide.html
(the search facility is quite good.....

)
Chris really seems to know his stuff and has posted lots of good advice on this forum. Jamie Porter also has a 156 buyers guide here:
Alfa Romeo 156 Buyer's Guide
which includes some stuff on the GTA.
Are you thinking of getting one? There are some nice examples around at good prices.
Cheers,
Nigel