I don’t want to throw it all out the window and end up over leveraged. 

Those new windows might be top of the line but i bet they'll break just as easily as the old ones.9) comps. i believe the general idea is if you can't find solid comps in the immediate area, you go with average price per sqft in the neighborhood.

During the inspection they did not find anything to suggest that the foundation has issues (i.e. no issues closing doors, cracks in walls, windows not working. 

even seen a sliding scale bid that they would go over any other offer by a $1,000, up to $30k over asking..   

For example, the deal we are working on right now we are replacing nearly everything (flooring, Air Conditioner, Electrical, Plumbing, windows, drywall, kitchen cabinets, full bathroom & the room has 20 years left). 

Risk and reward is real, I would rather have massive success with a few failures than 0 or a very modest return by window shopping.

If your properties are older you would need to consider the right amount based on the age of roof, furnace, AC, windows, appliances, etc.  

Since I'm heading into my third year of renting this property I am still within my window to avoid capital gains.

All 4 units completely remodeled, new roof, new plumbing, new electric, new windows.

All 4 units completely remodeled, new roof, new plumbing, new electric, new windows.