I had a 1993 GP SE with a 3.1 MPFI, which is slightly different than the 3100 SFI but i think the water pump and the hose locations are the same. I've never used a flush kit on any of my cars before, my flush procedure don't require it and besides my radiators have never gotten that dirty. Sorry, I don't know the inlets and outlets. I do know who would though. Go to The BEST Source For All Your GM 60ºV6 Needs and post over there. There are guys over there that can help you out and tell you which hose you need to splice in. Plus they can hook you up with performance modifications for that platforum. Good group of guys over there. I helped start that site with Ben Phelps way back in 2000-2001. I haven't been over there in years due to not owning that platform anymore. When I started messsing around with my 60 Degree V6 there wasn't a damn thing out there.
As for that metal/rubber heater hose line, back in the day (around 2000 or so) my rubber line to the water pump got a little soft. Instead of spicing into it I bought the whole section OEM from the dealer for like $30. It runs from the water pump, curves to a hard line, runs along the passenger side frame rail, runs half way against the firewall back to a rubber hose into the heater core. It was cheap IMO plus I replaced two rubber lines. It was really simple to install, bolted down in a few areas. While I was in there I replaced the other heater hose and both upper and lower radiator hoses too.
