THE basic idea behind XL-7 is terrific: stretch the Grand Vitara wheelbase to get a third row in, eke out more power from the baby Grand's V6 engine and throw in a vast amount of standard equipment - all for a price within sight of $35,000. Sadly for Suzuki, the Vitara heritage continues to plague it, with off-road prowess coming at the expense of on-road ability. A shortage of seating cleverness also restricts available space, spoiling an otherwise quite commendable and good-value package.