I think if you don't exceed the FUP quota, there will be no problem.

It depends how you judge the speed, if you use torrent speed as benchmark, I'm quite sure P1 does manage those services like other broadband operators.

I'm a regular internet user - no torrent and big file upload/download, I'm quite comfortable with the speed.

I did some speed test once a while and it's below my subscribed package, but I won't know it's below my subscribed package if I don't go and check it, and I don't really need to go check it because my regular activity is quite smooth for normal browsing and facebooking.

If not mistaken, anything going out to the public internet cannot be guaranteed by the ISP, they only can ensure within their network, there are no congestion up to the IP transit level.

The only correct speed measurement method would be a speed test to their local server. Second to that would be a server within Malaysia.