There are actually several differences in 4-53 x-head pistons, probably the 2 that you are looking at are pin diameters and port heights. The more expensive kit probably includes new bushings and pin caps for the larger diameter.
I usually use the .002" oversize liner on engines with high hours. You really need to know whether you have a former, current or silver style 4-53T. Your engine serial number will tell you this. The model number will look like this XXXX-X3XX. The 3 means turbo charged. Most good parts houses will give you the exact replacement with these numbers.
Also remember that you need to match your piston crown shape with the correct injector nozzle configuration. I have worked on several engines where the owners have tossed in huge 92 series injectors. All they have done is make lots of black smoke and totally whacked their hp and torque curve.