Both NASCAR Racing 2003 Season and NR2002 require a PowerPC system from around the time of their release, but will both run fine on an Intel CPU Mac running a version of Mac OS with built-in Rosetta emulator such as Mac OS X Snow Leopard. You cannot install Snow Leopard on a very recent machine though and Apple have removed Rosetta from later versions of the OS, so unless you use virtualization software such as Parallels it’s basically impossible to run NR2003 on a recent system without Windows.