The Red Firebird
Part of Lester's big life overhaul involves pursuing the kind of fun and passion he remembers from his teen years—and yes, that effort involves more than just fantasizing about a teenager.
One of his most dramatic moves (in Carolyn's eyes, anyway) is to purchase a 1970 Pontiac Firebird, which is the same bright, passion-y red as the roses floating around his fantasies of Angela.
The car's color is definitely a big clue that the vehicle symbolizes non-sexual forms of passion and excitement that Lester is pursuing as part of his new life. His self-confidence is through the roof when Carolyn first sees the Firebird, as he shouts "I rule!" because he was finally able to buy the car he had always wanted.