An inch is not going to affect it significantly and there are electronic devices (tonemonday.com offers one from AutoTrans) to correct the speedo and ABS calculations. The tires you mention will be way better than stock offroad but will be noiser onroad. The taller sidewall will cause a slight delay in abrupt manuevers. A wider tire really improves the look of the VX and a 275 or 285 is the max you can put on the stock rim. You can search for what others have done similarly along with impressions on most tires out there.