Should I fix the foundation in my rental?

[Zane Paul]

Far north Texas area, Grayson County 

Got the property very, very cheap. It was currently rented when I went under contract by a 5 year tenant. Many, many homes in the area have foundation problems from 4-7". I have toured some other units being rented and noticed the slab ones have faux-granite countertop, new cabinets, and decent sinking of the floors, and the pier homes (even the ones with repaired foundations) are wavy and all over the place.

I got the home $30,000 below appraisal. Not sure if it's worth fixing the foundation considering the condition of other homes in the area. 

I got 3 quotes from 3 contractors all suggesting different methods. 

1 - $23,000 - 47 concrete piers with rebar

2 - $6,500 - 38 concrete piers with steel support beams 

3 - $11,000 - no piers (more on that below), polyurethane injection 

Contractor 3 said piers aren't necessary as their is clear evidence that piers had already been installed previously. And the current foundation issue is a result of the piers on the east and west side being set too high, causing the home to "bow" which you can see by looking down the grout lines in the exterior brick. 

He recommended NO foundation repair, considering my plan to use it as a rental. Instead he said invest the money in re-grading the lot and replacing the driveway (currently cracked and sloped towards the home). That was already on my list of things to do, and he said it would be a waste of money to do any type of foundation repair until at least 12 months after the drainage issue is taken care of. 

So I plan to patch the cracks in the walls (some 1/8" or larger, diagonal from windows and door frames in one room, cracks appeared to be quite old), mud over the texture, scrape off the unpainted popcorn texture, and rip up the peel and stick floors to see what condition the slab is actually in. After all that and replacing the floors, as well as correcting drainage and replacing the driveway, and some other minor replacements I'm looking at about $10,000 in repairs. 

I don't think fixing the foundation is a priority for the next several years, I think I'm better off fixing the causes, putting makeup on it and waiting to see what happens in the area in 5-7 years, but I'd like some other opinions. 

Plumbing has been redone, it's all pex and the sewer line is pvc. Roof joists are solid, no cracks and the roof isn't pulling apart from the middle like is evident on some homes in the area so I feel like it's relatively stable as is.