I know your looking into the K&N filter for your 2.3Ranger but you may also want to have a look at the Volant intake as it can be had for considerably cheaper. They have one available for the 95-98 (which I bought) here
and for the 99-02 here
each for $99usd which is about 1/2 the cheapest I could find online or on ebay. I'm not sure if they are clearing them out or everyone else is just marking them up that much but I figured it was a steal at that price especially buying directly from the manufacture.
Thus far im very happy with it and it has made a noticeable difference for me both in higher rpm breathing and lower end torque. 5th gear is actually usable on a lot of the highway hills I tend to find myself on. My only complaint was receiving the usual ripoff from UPS all Canadians receive when making purchases from the US, and less than stellar instructions.