i have an explorer upper from a 97 and a lower from a 98 can i still reuse my factory egr valve and how should i route the hoses and would there be any leaks between the upper and lower since the upper has the hole in the middle of the runners on the underside

 

There are two "1998" lowers, one has the EGR the other does not.
If you want to use the internal EGR you'll need to use the lower with part number RF-F87E-9K461-BA.
I'm guessing the upper you have has the center EGR hole and if it does you're good to go.

 

the upper does the lower doesnt

 

It's not going to work for you then if you want to keep the EGR.

 

im going to track down another 96 lower

 

if i delete the egr would they work then

 

If you delete the EGR your CEL will come on unless you do a tune to turn it off at the computer.

 

but will it take away from drivability if i leave the egr hooked up

 

Buy a lower intake from a 93' Cobra, its all setup to be a simple bolt on and you can keep the EGR. An explorer lower requires you to drill and tap the #5 runner for the ACT sensor, so I hope your handy if your going that route.

Otherwise you can just delete the EGR all together, search google or Corral.net for how-tos/threads on what you need to do. You may or may not throw a CEL. My fathers 92' Stang did but all three of my previous Foxbodies didn't when I deleted the EGR. You can buy a simple 10$ EGR delete plug off Ebay that will trick the computer and take care of the light.