I might be wrong but i think its to do with the fuel Delivery, As the 2.2 16V sport.com is direct injection and the others are Multi point fuel injection see below
2.2 16V Sport .COM 3d - Production 8 Feb 2000 to 7 Dec 2000
Fuel Delivery - Direct injection
MPG 31
Engine Size 2171 cc
Cylinders 4
0-60 mph 13.3 s
Power Output 113 bhp
Valves 16
Torque 260 Nm 191 lb-ft
Top Speed 96 mph
2.2 Sport 3d - Production 20 Oct 1998 to 31 Oct 2001
Fuel Delivery - Multi point fuel injection
MPG 24
Engine Size 2198 cc
Cylinders 4
0-60 mph 12.6 s
Power Output 134 bhp
Valves 16
Torque 200 Nm 147 lb-ft
Top Speed 101 mph
2.2 Sport Olympus 3d - Production 1 Nov 2001 to 31 Dec 2003
Fuel Delivery - Multi point fuel injection
MPG 24
Engine Size 2198 cc
Cylinders 4
0-60 mph 12.6 s
Power Output 134 bhp
Valves 16
Torque 200 Nm 147 lb-ft
Top Speed 101 mph
2.2 Sport RS 3d - Production 20 Oct 1998 to 31 Oct 2001
Fuel Delivery - Sequential multi-point injection
MPG 24
Engine Size 2198 cc
Cylinders 4
0-60 mph 12.6 s
Power Output 134 bhp
Valves 16
Torque 200 Nm 147 lb-ft
Top Speed 101 mph
as i said i maybe wrong