High Performance Cars?

My customers have a 2010 Lexus IS F but my customers tend to drive slow in my customers city now a days. is this bad for my customers car? Maybe 35-45mph. Sometimes rarely my customers go 60. People are saying my customers have to open up the car once in a while Volvo Vocom 88890300.. But my customers don't really like doing that, Is that true? My customers just like the sound of my customers v8.