I would like to know what factors influence the performance of an IPO,
and what have been all the oil & gas sector IPO's over the last 2
years and there performance over the first day, the first week, the
first month, and the first two months of trading.  Also, how will the
Exco Resources IPO fare this week.

Oil and Gas IPO have performed very well over the past 2 years on the
back of the rise oil and gas price. There has been IPOs of
exploration/exploitation, oil services and refining companies, they
have all done fairly well.
You can check the chart of the following recent oil and gas IPOs to
have an idea of their performance : ALJ, BDE, BAS, BDE, BRNC, DPM,
DRC, NRGP, SWSI, WLL, WTI, WNR, WPZ.
As far as Exco Resources is concerned, it comes in a week where oil
price is going down and oil stocks are under pressure. It's a fairly
large IPO (50 mil shares)plus it's basically an acquisition company,
Exco owns a few oil and gas assets but their business plan is to raise
a big pile of cash trough the IPO and debt financing to acquire new
oil and gas properties. It's a proven and experienced management team
but an unproven business plan at a fairly rich valuation. It's
basically a blank check to the management hoping they are going to
make smart acquisitions.
I'd be surprised if it does well in the short term. I would stay away
from it in this environment.
Just my 2 cents...
JfinDallas