I believe that you will have to sue for the money, even though the note says that he gives up his right to notice and a trial. In the event you want to try to attach his assets or bank account, or use any other legal remedy, you will need a court order, and this can only be obtained with a lawsuit.
However, your lawsuit should be very easy to prove, and you will win in the end.
You can use procedures to try to attach his assets BEFORE he knows about the lawsuit. Since you have a signed agreement, you should be able to obtain an Ex Parte Attachment, which is an attachment of his property (bank account? house?) without notice to the defendant. The theory being that if he is notified, he will take the money out of the bank account, or transfer the property.
Since you know that he has no intention of paying, I suggest that you contact a lawyer and ask discuss an Ex Parte Attachment with him/her.
Since you have such a good case, you may find an attorney who will take your case in a contingent basis. A percentage of the money collected instead of payment up front.
Hope this helps.