issue with a XHR xml response in Google Chrome extension

Question

I am integrating Highrise into a Google Chrome plugin and have issues with a XHR responding xml.

I am pretty positive that Highrise API doesn't return a JSON.

I have a XHR in "background-script" , then I pass the result into "content-script" with a

chrome.tabs.sendRequest(tabId, {
    data :data }); 

and here is the issue I need here a JSON object, but I am receiving XML, so should I parse XML2JSON or is there a better ways to get the result.

P.S. I really need a performance, so don't really want to spend time parsing.