First off, you must decide if you want a Service Rifle (legal for Service Rifle - M1/M14/M1A/AR-15/M16 matches), or a rifle legal for John C. Garand matches. They are very different animals.
A rifle legal for JCG matches must be 'as-issued,' with no NM parts or glass bedding. A Service Rifle can have NM sights, heavy (stainless steel) barrel, glass bedding, modified gas cylinder/unitized front end, etc.
Read the rules, decide what type of shooting you want to be able to do competitively, and go from there. FWIW, and no flame intended, there are better barrels available than Wilson. Krieger immediately comes to mind.
You could pretty much buy an M1 from the CMP and compete in JCG matches with it. Many go that route and have a new barrel installed, and use new wood from Boyd's. You can also spend a pocketful of money on a rifle from Orion 7 or someone and compete with it out of the box.
A service rifle set up by one of the top armorers/gunsmiths will set you back a good $2K, minimum. Cheaper on your receiver, but not by a great deal. The wait will likely be a year or more.
Good luck.