As Ken noted, you don't NEED a Guru, but's really nice to have one in my book. But, I will second his suggestion to get the rotisserie. I held off until now (just received mine) and I can't wait to use it!
Like we tell newbies here: Don't fight it, just go out now and buy a bigger belt, because the amazing food you're about to produce on your KK will be so irresistible that you will need it!!