How to... upgrade your car's stereo - Professional in BMW 5 Series

BMW 335i SE £33,420

UPGRADE Professional LOGIC7
COST £1115
PCP COST £32 per month

The BMW's normal audio appears stingy given the car's price: the Professional system includes only a single-disc radio/CD unit and six speakers, although you do get an iPod-friendly audio input. Surprisingly, though, this set-up sounds very good; the presentation is fast, exciting and very musical.

Continuing the good news, BMW's charges for upgrading the hi-fi are relatively fair: a boot-mounted six-disc CD changer costs £295, while BMW's top-spec Harman Kardon Professional LOGIC7 upgrade system is £820, giving you a total possible upgrade cost of £1115 if you specify both.

Providing 13 speakers, and offering 420 watts of total power, this system also makes use of surround-sound audio processing to create a more involving sound.

Sonically, this set-up is undoubtedly better than the standard hi-fi, but as with the Dolby Pro-Logic II system used in the Volvo C70, we felt the LOGIC7 processing could introduce a slightly artificial feel to some music, particularly vocal-led tracks. It's great fun with dance and orchestral work, though.

The upshot is that, as with the Lexus system, the costs involved mean we'd probably choose to go without this particular hi-fi option.
RATING ***