i also had a 2004 grand sportage, i used to use delo gold as it's a very good universal diesel oil. as for washing, i use simple car wash shampoo which is available at all pumps. it gets rig od the grime from the body, but it is essential to polish the car after you ise the shampoo as it makes the body feel "dry" without polish.
BTW if you wand you car to be quieter while driving i'd suggest you get the fan coupling changed to a "cluth fan", this way the car is not always screaming like it does. i can't recall which exact clutch fan fit into my car but my mechanic at fire brigade sourced it for me. i think it was a toyota or mitsubishi part.
What colour is your sportage?