25% below actualy means 20% below because of the 5% buyer's prem

Like what VA said, set a maximum beforehand, and don't bid passing it.

Yes, there will be shilling bidders.  Once when I was bidding, there were several others, but the assistant autioneers only approached me to negotiate for a higher price for the property even others' bidding were higher.  Now I know they were just shilling bidders.

Also your 5% earnest money will be held for long time, so be prepared for that. I am still waiting for the seller's confirmation with my earnest money out there.  Mine was from auction.com, so the waiting time is supposed to be 15 business days maximum