The Biturbo name is no lie; this car came with a 2 liter engine with two turbochargers. The exported models (those leaving Italy) were made with a larger 2.5 liter or 2.8 liter engine. Those engines would have been taxed at a whopping 38% if they were sold in Italy with engines that large.
The North American version of this car could make 225 horsepower by 1989. The European non-Italian version made 250 horsepower.
When Maserati made the Biturbo, they were moving away from the supercars that they had become known for in the 1970's, and were moving towards a more affordable sports luxury image. The Biturbo achieved that, but at the same time alienated those few hundred fans of the supercars. It was still a hit with the general public, as 40,000 of the suddenly affordable Maserati were sold in the first year. Sales fell after that, but it was still one of the highest-selling Maseratis ever.
This car makes a cameo in the James Bond film License to Kill. It was also featured on an episode of Top Gear, when host Jeremy Clarkson claimed to have purchased one - and then promptly dropped a skip on it, destroying the car. He was one of the reviewers who hated the changed Maserati.
These cars are more common on the used car market than just about any other Maserati. You can find them on places like eBay, and you'll also find parts there. There are some Biturbo owners groups that will help you with a rebuild.