Fuel pump questions and tank size

Hi,
Looking to replace the complete pump/fuel sender unit in my 4 LITRE, 4WD 93 XJ, and want opinions on this unit: http://www.rockauto.com/catalog/mor...nid=424&jpid=7

Also it's states this unit will fit 20 gallon tanks. Did the XJ's come with different size tanks? My XJ is actually a used import from Japan, I live in New Zealand. If there are different size tanks, how can you tell the difference?
Thanks

If I remember correctly the only difference in the twenty gallon tank and the sixteen gallon tank is the fuel filler hose. A simple mod is to drop the tank and cut off about half of the vent tube in the tank. The actual tanks are the same. Someone else may have more info but that's what I did to my 87 and then it would hold twenty gallons. Good luck and remember, you need to cut the filler tube vent in the tank about halfway and remove.