you are correct, but as stated my car wasnt getting up to temperature, but I believe this was due to a 62deg thermostat, Mishimoto ally rad with twin fans etc. I have now swapped the 62deg stat for a Mishimoto 67deg and seemed to help the car warming up before I took the cooler off.
I would also agree, not the best time of year to be selling something like this, this side of xmas....
What you were finding was the water wasn't getting upto temperature which is probably down to both the fans and also the oil temps being too low to sustain the required water temp.
If you fit an oil temp gauge you will be surprised how low the temps will be with something like this fitted.
I went for a 13 row cooler as I thought the bigger one was probs over kill.
If somebody wants to buy this for a daily, in the winter I'd recommend covering the cooler to block the airflow. This will allow the temps to come up as required probably.
This is probs what I will do if I'm using it for a run in the winter.
This kit is far more superior to the one I bought and has all the extras. Mines was very basic and more parts will be required to fit. If you don't sell it soon I may buy it off you at a later date to steal some of the bits from it for fitting mines.
Good luck with the sale mate