         parameters: Dictionary<String, AnyObject>,
         dataEncoding: NSStringEncoding,
         body: NSData? = nil,
-        paramsLocation : ParamsLocation? = .AuthorizationHeader) throws -> NSMutableURLRequest {
+        paramsLocation : ParamsLocation = .AuthorizationHeader) throws -> NSMutableURLRequest {
             for (key, value) in headers {
                 request.setValue(value, forHTTPHeaderField: key)
             }

        self.init(URL: URL, method: .GET, parameters: [:])
    }

    init(URL: NSURL, method: Method, parameters: Dictionary<String, AnyObject>, paramsLocation : ParamsLocation? = .AuthorizationHeader) {
        self.URL = URL
        self.HTTPMethod = method
        self.headers = [:]

            let charset = CFStringConvertEncodingToIANACharSetName(CFStringConvertNSStringEncodingToEncoding(dataEncoding))

            let finalParameters : Dictionary<String, AnyObject>
            switch (paramsLocation) {
            case .AuthorizationHeader:
                finalParameters = parameters.filter { key, _ in !key.hasPrefix("oauth_") }
            case .RequestURIQuery:
