You can change your network card just to be sure.
For me, it was perfectly fine as well, till the lost connection and subsequent bugs suddenly started to appear.
Without any kind of warning, without any kind of software + hardware update.
I've changed my network card, doubled my bandwidth on international servers & co. and nothing.
I've did some testing yesterday, played Source on a server with 40 players, somewhere in Asia, with 400 ping. Luckily it was no ping limit, and for the sake of testing I've stayed there with the unbearable lag.
Than played Live for Speed demo on a full server.
YahooMessenger open, net browser open etc.
Absolutely no kind of issues with my connection.
In Race07 though, there's a few minutes delay in multiplayer mode, lost connection, drop-outs, it's like a nightmare.
I have to press 20.000 times the join button and no response.
Not to mention I'm getting spawned with the safety car and I'm making balet and acrobatics, colliding with her.
This is a new bug added to "lost connection" consequent bugs.