I love the look of the M3 w/o the stripe kit and the clean lines. However like others have stated, it's your preference and your car.
I completed some mods to my Z4 and others have ripped it apart. I take it with a grain of salt and forge ahead to my personal mods and taste.
Go For It.
2009 BMW Z4 35i/Space Gray Metallic/7 Speed DCT/Premium,Cold Weather & Premium Sound Packages/Nav/Comfort Access/Ash Grain Interior & Dash Kit/AntiTheft/SportWheel/PDC/WindDeflector/Black Kansas Leather/Smoked Reflectors, Side Markers & 3rd Brake Light/Ferrari Red Brake Calipers/Clear Front Mask/Gloss Black Grill Inserts/6000K LED Lighting/De-Badged/Aluminum Pedal Set/Real Carbon Fiber BMW Door Sills/CF Wrapped Engine Compartment Roundels,F Lower Grills & Center Wheel Caps.