The shipyard that made the boat was a very reputable one. The made for many years the APHRODITE 414 that was a great boat and still a very popular one. The Shipyard had been building boats from 1964 to 1994 and still exists as a repair shipyard, as a family firm.
The Danish shipyards are known, even today, by a superior workmanship and the possibilities are that the Bianca 36 is a very well built boat. It seems a very nice boat to me, considering early 80's.
Regarding speed potential you can see here:
They use a rating called LYS, the bigger the number the faster. It seems a faster boat for its time with a LYS of 1.15. A Bavaria 34, a 2000 boat has 1.16, a 2000 Dehler 36 (a fast boat) 1.29, an old Dufour 3800 1.10, a First 35 1.18, a more modern First 36.7 1.29, a HR 36 1.15, a Hanse 341 1.21, a Najad 360 1.10, a Swan 36 S&S 1.13.
I guess this will give you an idea about the boat sail performance that was good for a boat from the early 80's.