Can someone tell me which of these antenna adapters I need to install a Sirius FM direct adapter in my 2000 Pontiac GP w/ OEM radio? http://www.aislebuyaisle.com/advanced_search_result.php?keywords=gm+antenna+adapter&category= I'm not sure what the difference is between the antenna dapters in the kit, the $2.50 adapters, and the $5.00 adapters. Thanks. S.
