Welcome to the forum.
I'm not familiar with the Mahindra models but can toss out my general experience.
If you want a backhoe, it's best to get the TLB package. Aftermarket or adding on later doesn't seem to work as well for the reasons you specified (cost, plumbing, sub-frame...). An exception to this is some of the Woods brand backhoes.
Look closely on how easy or difficult it is to take it on and off. Get the dealer to do a demo if you can. If it's a PITA to get off and on, you'll normally leave it on but that hinders your capabilities for other PTO or 3PH implements.
Decide on whether you want or need a backhoe. Look at your projects. If you're building a buying a place that needs a lot of work, you probably need it. If it's for doing things here-and-there, you probably just want one. In this case (want), look at what your options are for renting or borrowing one. Renting a TLB of about the same size is (around here) about $100 per day, delivered. You can do a lot of digging for that $100 if you save your projects up then knock them all out at once.
If you are going to get it, do internet searches for that backhoe model, in particular how strong or robust it is. I've seen a lot of these smaller hoes get torn apart, bending steel or pins doing what you think it was made for.
Good luck and let us know how it goes.