I had forwards on my 800 for a time, but took them off. I liked the extra leg room, but felt I could not countersteer in the mountains as well sitting in a more reclined possition. I also lost some ground clearance, and dragged the forwards a lot more than I ever dragged the stock pegs. I LOVE blasting across a twisty mountian road at high speed, so the forwards just were not for me.
So I sold the forwards and put on some highway pegs that attach to the frame without engine guards, and have the best of both worlds.
If you have long legs, and feel cramped, you will really enjoy the forwards. Around town, they certainly are cool looking, and give you a laid back riding possition. But if the bike is comfortable for you now, you may be like me and find you like the highway pegs better.
The best advice I can give you is to find someone else with forwards, and sit on their bike and maybe see if they will let you take it for a spin. If you do buy some, retain all the stock parts so you can go back if you want.
The Restyling brand forwards are the most affordable for the Intruder, and they are easy to put on and take back off.