1. Wrong concept. 
Physical gold you buy at Rm200, even the spot price up Rm10, let say RM170 to RM180, you may only can sell back at RM180, not RM210.
Who is the person to buy at RM210 from you?
Unless you become the goldsmith to sell at retail price. But this is like doing business trading already, not investment, or sell back.

The real worth of gold is based on spot price, nobody want to buy above the spot price.

Physical price is always based on spot price or paper price, there won't be disconnection issue.
As if there is, many will take advantage of the spread and correct the market back.
Market is always efficient, you let people to have change to do arbitrage, the price correction come it to reconnect back.

Yes & No.

Gold has its dark day as well. Gold never rise steadily period from about 1980 to 2002. It stagnant throughout 20+ years. While others investment asset give more than 200-300% (even for pathetic FD) or even more for properties, stocks etc.

Gold is not a backbone of monetory system.
Printed money is not backed by gold. Although more gold in the coffer can instill confidence on your money. But printed money is not backed by gold.
Also there is not enough gold to back all the money out there.
Gold exist or not, doesn't alter the current financial system.
Gold is just another investment class out there in the financial system.

Use gold to measure against goods, price never change?
I don't know the answer, but I only know,
1980 1ounce of gold cost USD 300, while a bowl of hawker mee, cost RM0.20
2011 1ounce of gold cost USD 1700, while a bowl of hawker mee, cost Rm4-5.

So price got chance or not? 

now ppl invest 999 gold or 916 ? i c lots of different kind of gold offer  from bank like 999 pure gold, 99.5 gold, and read some forumer mentioned about swiss pam gold, kijang gold. which one is the best to invest to? any sifu can guide me?