I have a KTM SW400, so I like your screen name.
Here's my 2 Cents: Start with the basics and work your way up. I have been reading 100s of posts here from guys that are spending thousands and thousands for walls, sound deadening, stages, paint on ceiling with integrated LEDs, etc, etc etc. All well and good once you have your other options covered. But to begin, you have to get good equipment to build upon. Get the basic setup done first and then add the details. Don't let the details eat up your budget before you get the good reference speakers or the projector that will give you an amazing picture. Wall sconces will do you no good if your picture is distorted with a bad screen, or the audio sounds off because you skimped on a 100 dollar amp.
Not all of us can afford a $100,000 theater, so start with the base elements and then build up from there.