Well, depending on your countries law you might get serious trouble.
So if you want to use it from home, also think about the vast number of DNS requests. Although I used my home computer in the beginning, I am not to scared. If you are not, then you might do the following in ascending order considering security:
1. use XR from home, but with proxies.
2. use XR and a VPN service: most VPNs offer max 5MBit/s an will shut you down, if you do not use proxies
3. use XR and VPN on a small box, but with huge traffic
Extra security: use a free DNS server (might shut you down when you have too many requests).
RAM is important if you want to use the antispam feature, which gets more and more important. Pure spam links are not worthless, but not worth the effort.
QuadCore + 20MBit is very fine.