After a couple of presumably uneventful years driving for Salieri, Tommy is approached with a special request from the old man. Salieri's got some serious cash riding on an auto race, but one of the new entrants worries him. Some European hotshot has entered the race with what might be the fastest car in the world, and Salieri can't allow an unfair advantage - especially when it's an advantage against him. Salieri therefore asks Tommy to sneak onto the speedway, steal the car and take it to a mechanic named Lucas Bertone for some modifications. (Bertone, by the way, is instrumental for the rest of the game in giving Tommy side missions and helping him steal better and faster cars.)
The operation goes off without a hitch, but the next morning, Salieri's favored driver shows up with a broken arm. It turns out the entire neighborhood was backing Salieri's driver as well, so in order to save face, Tommy is ordered to enter the race - which, of course, he wins.
Following his success on the track, Tommy meets Sarah, the daughter of Salieri's bartender, Luigi. Some nights later, Luigi asks Tommy to walks Sarah home; it seems some local thugs have been menacing her, and she's worried for her safety. Sure enough, her worries are well-founded, and the punks show up to harass Sarah and Tommy on the walk home. And when they get violent and try to assault Sarah, Tommy goes ballistic and kicks all their asses at once. Naturally, Sarah gets really turned on by all this, and after she dresses Tommy's wounds we're treated to a vague, bare-shoulders love scene that predates Mass Effect's hot alien action by a full five years.
What happens next is one of the most pivotal events in the game: Salieri isn't happy with these punks trying to make trouble on his turf, and so he orders Tommy and Paulie to send them a message. One delivered to kneecaps, by baseball bats. Unfortunately, the plan hits a snag when some of the gang members turn out to be packing heat, and Tommy and Paulie have no choice but to return fire. Even more unluckily, the last hood they kill turns out to be the son of a city councilman, and the only surviving punk witnesses the murder. This is what we call "foreshadowing."
Soon, Tommy's assignments begin to take on a darker bent. Salieri's consigliere, Frank, approaches Tommy with orders to murder the owner of a high-class brothel, who has recently decided to switch his allegiance to Morello. To make sure that the message is clear to anyone considering a similar change, Tommy is to then blow up the manager's office and escape. And while he's at it, he'll need to murder a prostitute who's been passing information about Salieri's activities to Morello.
After entering the hotel, gunning down the owner and making short work of the guards, Tommy finds the girl's room and confronts her in her bathtub - only to find out that she's Sarah's best friend, Michelle. Already uneasy with the idea of killing a woman, Tommy decides to let her live, on the condition she leave town and never show her face again.
Quick note to all soft-hearted would-be assassins: as innumerable gangster movies have taught us, this will always, always come back to bite you in the ass.
Tommy's conscience doesn't keep him from bombing the dead manager's office, of course, and as the hotel's top floor erupts in a huge fireball, Tommy escapes by leaping through a plate-glass window. It isn't long before the cops show up, and an extended shootout across the nearby rooftops ensues. Finally Tommy manages to make his getaway through the open, under-construction steeple of a nearby church.
Of course, these things never go smoothly, and the church just so happens to be playing host to the funeral of the punk Tommy and Paulie killed the other night. The surviving kid fingers Tommy as the murderer, leading some of the mourners to open fire (as you do). After turning the church into a slaughterhouse, Tommy is confronted by a priest who asks him why he's committed so terrible a sin. Shrugging off the criticism, Tommy hands the priest a wad of cash to pay for the damages and leaves.
After the massacre, Tommy and Paulie start to descend into a nihilistic haze of binge-drinking and excess, which continues until Frank shows up and pulls Tommy back from the brink. While subtly warning Tommy about the dangers of alcoholism, Frank tells him to settle down before his behavior gets him killed. Tommy apparently takes the advice to heart, and the two men become friends.