My parents just bought a brand new 07 Volvo C70 a couple weeks back. My mom wants some better speakers, do any of you know what it takes and how hard it would be to integrate into the stock radio?

How's the reliability on the turbocharged I-5? I imagine the engine is based off the same architecture of the S60R engine but detuned. Are there any cheap/free HP mods for it? Its my mom's daily driver but my dad cant wait for her to break it in so he can give it hell (me too ). I told him to at least get a K&N filter for it if nothing else.