about pump quality ....like josh said buy what you can with what you got but if you buy a new pump try to by a good one .the first one i installed was a no name brand and it failed on me 3 days after installing it ( $99 and a 6 month warr. ) the next one i bought at advance auto was a bosch it cost $30 some odd more but comes witha lifetime warr. !! have not had any issues yet .
btw : dropping the tank may sound like bit-h but it's really not ...if i have all my tools in front of me and the truck lifted i can do it in about 45 minutes same to re-install ...2 hours tops from start to finish( with all the gas out of it of course) .one of the best things dropping it will let you clean it out really well .not just sticking your hand in there to clean what you can see . when i did mine i washed it out inside and out and then got some lint free towles and dried it then i got my air compressor and blew it out to make sure it was all good.
mine did not have a lot per-say debrie in it but around the pick up tube / screen area was ring of really fine sandy type stuff that was glued to the tank ...had to scape all that crap out thus the need to flush the tank .burns came up with a good idea don't get me wrong (( not trying to dis you burns )) ( almost wished i did that first off ) but dropping lets you do many things ,being able to clean it really good ,lets you inspect all of the tank like where the skid plate is ( mine had rocks between the tank and skid plate ...nothing like haveing a sharp knife on a PLASTIC FUEL CELL ) ,and your not cutting a possible rust latent hole in your unibody ( and not to mention that the possiblity of cutting your tank while trying to make the access hole .
hope this helps . . .