I am condsidering purchasing a Hitachi DS18DMR cordlees drill but when I search for it sometimes I see the same model with a PS at the end(Hitachi DS18DMR PS). Does this mean there is a difference?

I can't answer the difference, but I found this a few days ago. You may want to look at it before you buy.

Cordless Drill Review - Dewalt, Ryobi, Makita and More Cordless Drill Ratings - Popular Mechanics (http://www.popularmechanics.com/home_journal/tools/4292657.html)

Hi,
Hitachi does not help much; the PS is in parentheses. See:
HITACHI Power Tools: Products > Cordless > 18-Volt > DS18DMR(PS) 18V Cordless 1/2" Driver Drill, 2.0Ah Batteries (http://www.hitachipowertools.com/store_item.php?iID=552&arrPath=1,2,20,p552),
Peace,
Clarke

I can't answer the difference, but I found this a few days ago. You may want to look at it before you buy.

Cordless Drill Review - Dewalt, Ryobi, Makita and More Cordless Drill Ratings - Popular Mechanics (http://www.popularmechanics.com/home_journal/tools/4292657.html)

Thanks for sharing this with me. I have not yet made a purchase but this will help me decide.