I'd greatly appreciate any experience-based advice available and appreciate to a question that will probably make very obvious how new I am to modifying/improving my vehicle audio and how little I know. Thanks, in advance, to any and all who are willing to humor what is probably a very silly question.

I just took delivery of a new '07 HHR that will primarily be a business vehicle. It is equipped with the factory CD head unit with XM and has whatever GM includes with their 7-Speaker "Premium" Audio option. It's perfectly acceptable for non-audiophile system and more than adequate for my meager tastes. However, I've noticed its reception of AM stations is not nearly as sensitive as my other vehicles.

To further clarify, I'm sure it's not malfuctioning; reception for local AM is exactly as one would expect. However, this unit doesn't seem to be able to receive those nighttime "far away" stations I've always enjoyed in my other vehicles when the weather and environment has permitted. I presume one answer is an AM signal booter that makes an antenna of the vehicle wiring alongside the standard antenna. I've seen many devices claiming to be "boosters" on eBay and elsewhere, but I get a "snake oil" feel to much of the performance claims, and price doesn't always seem to correspond with performance promises. While I certainly don't expect to get any more than I pay for, I'm not so naive as to accept that "more expensive" is any guarantee of "more peformance". Prices range from $8 on up to $100 or more.

Can anyone make a recommendation as to an antenna/signal booster that has delivered good, tangible results? With all else being equal, I'd prefer one that doesn't require a power source, but I'm absolutely not opposed to whatever solution is most likely to deliver the best outcome. I'd say the only absolute is keeping my existing tuner/head unit as not to change the interior appearance.

Again, I know this may be a painfully stupid question; but I hope, and would appreciate it if, there is anyone with the experience and patience to offer some guidance.

Thanks in advance,

Remmie