no, its actually something they still do and advertise
Yeah, "Speed Boost" is a totally different thing from their deep packet inspection and other questionable past and present practices. i.e. sending RST packets to kill BitTorrent downloads.
What makes you think that it's deep packet inspection when they shape old connections, but not when they shape new ones?
They never used RST attacks against me, or targeted BT; it was really simple shaping. If you saturated your upstream bandwidth, they'd choke your downstream so the buffer would overflow and discard ACKs (read: lag). It affected everything, but BitTorrent swarms are incapable of thriving in high-latency environments.
The FCC ruled that packet shaping of any form is illegal. Obviously, the questionable practices were what they were targeting, but speed boost begets false advertisement, and so it's also illegal.