If you agree lump-sum, then as long as the contractor is using agreed-upon materials where he sources them and for how much is between him and his supplier.

.* Turn key companies get large discounts from material and HVAC suppliers that the individual does not.* Turn key companies can negotiate better rates with their contractors and trades people* There are no construction overruns or surprises when you buy a turn key property* There is no tenant lease up fee with a turn key.

IE they don't have net 30 accounts set up at their suppliers they are cash and carry etc.then you have contractors that have established credit a team of very established subs.. but these guys will be higher priced and since rehabbing is about how cheap can I get it done if you go this route many times the numbers don't work but you get what I call true professional contractors.So when we fund rehabs its pay as you go .. and its totally a relationship and trust issue.

You'd be better finding a smaller contractor that can get nicer siding from the supplier and have them install it, saving you some money.

We recently rehabbed our home and purchased a LVP brand called Naturally Aged Flooring from a local supplier (https://www.naturallyagedfloor...).

I do about the same number of rehabs you do...about one per month, on average.We use the same two crews on everything as well, but they don't include a GC and don't include some specialty trades, such as:- Licensed Plumber- Licensed Electrician- Licensed HVAC- Cabinet Supplier/Installer- RooferSo, we use our main crews for about 80% of the work, and then also have to schedule and manage these other specialty trades.

You could also call some of the national carpet suppliers like empire or national floors to see what they'd charge. 

Try to find some slab granite pieces in the boneyards of the suppliers.

For contractor references I usually find its best to go to your local building supplier and ask who they recommend. 

tobonsai.com  -  Haven't tried them yet so can't give a first hand review, but after listening to the owner interviewed on a STR podcast it seems that he has thoroughly vetted suppliers to get a good product to STR owners.