Guy, If your friend with the 1800 is riding year round and running heated gear and extra lights and such, Compufire is the way to go. I've had one on my 1500 for years. No problems. I have a gauge on my bike, and with the Hotgrips on, electric vest and Tulsa lights on, it stays in the green. He will need a sealed battery such as an Odessy to go with the higher output of the Compufire. As for the front forks on the 1800, you need someone else to chime in. I have Progressive front and rear on my 1500 and am happy with that set up.
1997 Honda Valkyrie, 1998 Kawasaki KLR 650