From my personal experience, you don't need Thunder / Xunlei with BolehVPN. However, don't take this as an official statement that you'll get max speeds. I suppose it'll work, but uTorrent works just as well, and it doesn't hog resources like Thunder / Xunlei.
Depending on your routing and your luck, you could probably get 200 kB/s or more total download speed. However, currently the ACPN2 issues are affecting a lot of people, and your download speed may not max out.
Again, a personal experience: BolehVPN let me max out my bandwith at 165 kB/s for my 1.5mbps package.... A significant improvement from 40 kB/s, don't you think?