AVS (Active Variable Suspension) is only available on the IS350 F-Sport (RWD and AWD). It is not available on the regular IS350 or the IS250 F-Sport. This the main reason to get an F-Sport and again, it's only available IS350 F-Sport. AVS is activated when in the Sport+ mode.
VGRS (Variable Gear-Ratio Steering) is only available on the IS350 RWD (either base or F-Sport), although it's more common on the F-Sport varient.
The 8-Speed transmission is only available on the IS350 RWD (base and F-Sport), with everything else getting the 6-Speed tranny.
That being said, I own a IS350 F-Sport RWD with VGRS and it's awesome.👍👍 The AVS and VGRS in conjunction with the great 8-Speed tranny makes the F-Sport worth the extra money.