Starwood Preferred Guest - About SPG elite status...

1. Can I obtain SPG gold or platinum membership by spending enough on my SPG amex card ??? If yes, how about the limit I have to hit???

2. According the website, it says "a 50% bonus over Preferred Guests". Does it means after I become SPG gold/platinum, I can earn 1.5 SPG points per every dollar spending on shopping etc?

Thanks

1. Can I obtain SPG gold or platinum membership by spending enough on my SPG amex card ??? If yes, how about the limit I have to hit???

2. According the website, it says "a 50% bonus over Preferred Guests". Does it means after I become SPG gold/platinum, I can earn 1.5 SPG points per every dollar spending on shopping etc?

Thanks

Please see here: http://www.flyertalk.com/forum/starwood-preferred-guest/720571-spg-american-express-master-thread.html

But to answer your questions:
1) Yes, $30,000 Annually. You will be upgraded to Gold Elite.

2) No, the 50% bonus applies to Starwood Hotel Stays, normally you earn 2Starpoints/$1USD, with Gold/Platinum you will earn 3 Starpoints/$1USD at Starwood Properties. These points are earned through SPG, not AMEX.

SPG AMEX will earns 1 SPG/$1USD, and 2SPG/$1USD @ Starwood Properties, no matter what your SPG status is.