Sponsor renovation or own contractor

I'm very interested in a one-bedroom apartment that's a sponsor unit. For an additional $26,000, the sponsor will redo the kitchen (new cabinets, appliances, granite countertops), and gut the bathroom. They'll also change the doors and do a few cosmetic upgrades. Is this worth the additional $26,000? Could I get this done on my own for less? I probably won't have too much say in the type of appliances/furnishings, and I'm not sure about the quality of the work. There are definitely things I'd like to do that are not included in this renovation (add a few more closets, maybe convert from a tub to a shower). On the other hand, the cost of the renovation would be factored into my mortgage, and I'll have a newly renovated place at closing. Any advice would be much appreciated!