What someone paid for something has no bearing on it's value, if you paid $100k rather than $10k that wouldn't change what you could sell it for.  

Can anyone give me an guesstimate on what it would cost to replace a load bearing beam in a basement that is 50 feet long.

If I needs more than we thought and more than the numbers can bear, then we either lower our offer or we cancel the contract.  

This cost variability depends on factors such as system design, property size, soil type, and system capacity requirements.

Because we know that these issues have little bearing on the property market and because we look at facts and statistics instead of basing our decisions on hearsay and fear mongering:- We know that many North Americans have invested there and the overall majority has never had any problems with it;- We know that, if we invest in the right places, we will make much higher capital gains that we can get in Canada or the US over time;- We know that tourism numbers keep increasing year after year, whereby we'll make a great return with short term rentals;- We know that more and more North Americans move to and retire in Mexico, to take advantage of the great weather, culture and the cheaper cost of life;- We know that our property is safe and isn't gonna be taken away from us.To conclude, I'm not going to try to convince you to invest in Mexico.

If not, you may be better served NOT to prepay for the reasons others have mentioned - the renter pays your mortgage, so the cost of funds is not yours to bear, and the cash in your hand can be deployed where it does you the most good.

If I am reading this correctly, your recommendation is to get the soils report and speak with a structural engineer to estimate a grading, retaining, and foundation cost.

The soil has been tested and it's ok.  

Does the W2 income being greater than $150k have any bearing?

LLC is for asset protection and has no bearing on your taxes.