I ran my first site in a PVP Gila with just a invul (was off due to nuets) and 2 Extenders , it tanked a Full 3 BS wave once I killed the smaller stuff. Once you kill the small stuff you barely need any tank at all (sub 100).
If you want hard go and run a real sleeper site with Safeguards ect, Some C3 sites put out over 1K DPS and C4 over 1900 (C5s and C6s have more again), these sites are very easy in comparison.