I've used ThreatFire with Avast Home and they ran very well together. However, I have recently been using Comodo Pro 3.0 with Defense+ and Avast instead and my browser is faster than with TF. Some people have actually used Comodo and TF together, but I think this is overkill. BOClean runs light with Avast and Comodo, but again I'm not sure I need any extra protection because of what all Avast Home detects.