Where are you located and what will a local machine shop charge to rebuild the engine, 4.0l SOHC engine is not uncommon, if possible check a few local shops.
Nothing wrong with mail order parts/engines in general, but................engine warranties can be a bit tricky, especially if you are not a professional mechanic and will be installing the engine yourself.
Even professional mechanics can run into problems with mail order parts.
Outside of some specific failures, which is always at the sellers discretion, "installation caused problem" seems to happen alot, lol, and warranty won't cover that.
And warranty doesn't cover labor on your end in any case.
Local machine shops usually treat you a little better because "you know where they live", lol.
But no, I don't know anything good or bad about Promar Engines, it does say there is extra shipping charges if you don't have a forklift or loading dock where engine(core) is to be picked up and dropped off(new one)