The Mahindra XUV 7XO is a well-rounded product, and the AX7 T is the variant to choose as it offers all the premium features you would expect at this price point. You get a 16-speaker Harman Kardon sound system, ventilated front seats, Level 2 ADAS, an electronic parking brake and much more.

As for whether you should opt for AWD, it really depends on your usage. If you live in the hills or regularly drive on challenging and slippery terrain, the AWD version can make sense. For most driving conditions, however, the Front Wheel Drive version will do just fine.

If your idea is to get into serious off-roading, the 7XO is not the best choice, even with AWD. For that kind of usage, the Mahindra Scorpio N or the Mahindra Thar Roxx, with higher ground clearance and a low-range gearbox, will be far more capable.

The Mahindra Scorpio N would meet your requirements of a diesel, rear-wheel-drive, 6 or 7 seater, while the low to mid-variants will come in below your Rs 20 lakh budget. 

The Scorpio N has few options in a 6-seater configuration, but multiple 7-seat variants are on offer that you can choose from. Given that you drive mostly on highways, the strong performance from both the petrol and diesel engines will easily satisfy you. Also, between the two, we would recommend the diesel given its better efficiency while still delivering well on refinement and performance.    

Out of the three options, the Tata Safari is the one to go for, for its excellent ride comfort, both on the highway and in urban conditions. It feels tough, and flattens bad roads very nicely. 

Moreover, it is more comfortable in all three rows than the Mahindra Scorpio N. Tata's 2.0-litre diesel engine is punchy, although the Mahindra car has an edge in terms of refinement.

The Force Gurkha is the most rugged of the three, and the most capable off-road. But since you want a car for on-road driving, it is also the least comfortable, feels utilitarian, its diesel engine lacks performance, and there is a lot more body roll than the other two cars.

For your 500km monthly journey and once a fortnight over 100 kms drive, you can go for either Mahindra XUV 7XO or Scorpipo N Diesel. 

They are great long distance car, excellent highway manners and matching performance. I must tell you, Mahindra is launching the updated XUV 7XO on January 5th and the Scorpio-N update is expected sometime early next year. 

Keeping that in mind, we suggest you wait. If you want to go for the current models, you can negotiate with the dealer for a better price. 
 

We think you can wait for the Mahindra XUV7XO launch. Since this is a facelift and not an all-new model, some of the initial issues that customers often face with fresh launches may not be present. 
Tata Harrier has some ergonomic concerns, and with your height, you may find it difficult to settle into a comfortable driving position on long journeys. If teething issues with the XUV7XO facelift are a concern, the Mahindra Scorpio-N is a sensible alternative to consider.
 

The Mahindra Scorpio N is a tough, dependable SUV built to handle rough terrain with ease. 

Its body‑on‑frame construction gives it the strength to handle rough roads and punishing conditions. Prices start at around Rs 16 lakh and go up to about Rs 28 lakh for the top‑spec Z8L variant. 

You can choose between powerful petrol and diesel engines. But if you plan to buy one, the 2.2‑litre diesel remains the better option for its strong torque and efficiency. Unlike the older Mahindra Scorpio Classic, which continues to be on sale. The new Scorpio N has a forward‑facing third row and a cabin that feels hard‑wearing yet well-equipped. 

The ride quality can get a bit choppy on uneven surfaces, and it does lean through corners, but overall, it’s a solid, go‑anywhere SUV that’s built to last.