diff --git a/client.js b/client.js
index f1ff3040..6a628c0f 100644
--- a/client.js
+++ b/client.js
@@ -53,6 +53,9 @@ function Client (peerId, port, torrent, opts) {
 
   self._rtcConfig = opts.rtcConfig
   self._wrtc = opts.wrtc
+  self._userAgent = opts.userAgent
+  self._key = opts.key
+  self._statsForAnnounce = opts.statsForAnnounce
 
   debug('new client %s', self._infoHashHex)
 
@@ -262,11 +265,15 @@ Client.prototype._defaultAnnounceOpts = function (opts) {
 
   if (opts.numwant == null) opts.numwant = common.DEFAULT_ANNOUNCE_PEERS
 
-  if (opts.uploaded == null) opts.uploaded = 0
-  if (opts.downloaded == null) opts.downloaded = 0
+  var providedStats = self._statsForAnnounce ? self._statsForAnnounce() : {}
+
+  if (opts.uploaded == null) { opts.uploaded = providedStats.uploaded || 0 }
+  if (opts.downloaded == null) { opts.downloaded = providedStats.downloaded || 0 }
+  if (self._key) { opts.key = self._key }
 
   if (opts.left == null && self.torrentLength != null) {
     opts.left = self.torrentLength - opts.downloaded
   }
+
   return opts
 }
diff --git a/lib/client/http-tracker.js b/lib/client/http-tracker.js
index b82691f0..d59386fd 100644
--- a/lib/client/http-tracker.js
+++ b/lib/client/http-tracker.js
@@ -41,15 +41,20 @@ HTTPTracker.prototype.announce = function (opts) {
   if (self.destroyed) return
 
   var params = {
-    numwant: opts.numwant,
+    info_hash: self.client._infoHashBinary,
+    peer_id: self.client._peerIdBinary,
+    port: self.client._port,
     uploaded: opts.uploaded,
     downloaded: opts.downloaded,
-    event: opts.event,
+    left: opts.left,
+    numwant: opts.numwant,
+    key: opts.key,
     compact: (opts.compact == null) ? 1 : opts.compact,
-    info_hash: self.client._infoHashBinary,
-    peer_id: self.client._peerIdBinary,
-    port: self.client._port
+    event: opts.event
   }
+
+  if (!params.key) { delete params.key }
+
   if (self._trackerId) params.trackerid = self._trackerId
 
   self._request(self.announceUrl, params, self._onAnnounceResponse.bind(self))
@@ -86,10 +91,15 @@ HTTPTracker.prototype.destroy = function (cb) {
 
 HTTPTracker.prototype._request = function (requestUrl, params, cb) {
   var self = this
-  var u = requestUrl + (requestUrl.indexOf('?') === -1 ? '?' : '&') +
+  var headers = {}
+  var url = requestUrl + (requestUrl.indexOf('?') === -1 ? '?' : '&') +
     common.querystringStringify(params)
 
-  get.concat(u, function (err, data, res) {
+  if (self.client._userAgent) {
+    headers['User-Agent'] = self.client._userAgent
+  }
+
+  get.concat({ url: url, headers: headers }, function (err, data, res) {
     if (self.destroyed) return
     if (err) return self.client.emit('warning', err)
     if (res.statusCode !== 200) {