Hi Pete,
I'll try to come at this from an IMA point of view...

You say that your martial art training has made you more competitive - IMO, this is the root of materialistic wants. Competing fosters the desire to "win", and the winner gets the "trophy". Carrying this over into real life, you are wanting to "win" all of the best "trophy's" you can, such as the big house, the big car. Like a shiny gold trophy on your mantle, a 5 bed detatched in Surrey with an Aston Martin in the drive is a symbol of your status, your power - your success in the competition of life.

So, IMO, to rid yourself of material wants, you need to train your mind away from competitive thinking.

Thoughts?