i think because you don't have a high HP car and also your weather is the type that your cars will see snow. i would go with rubber bushings, but upgrade to the M3 ones and maybe limiters.
i have the poly ones and have no issues or squeaks. love them. but in climates that see varying weather with salt and water i might be worried about it's effect on the bushing and grease. then you might introduce possibility for squeaks. which means you have to lube them again compared to maintenance-free oem style rubber bushings.
OE CSL WHEELS - OE CSL BRAKES - OE AUTOFOLD MIRRORS - CSL TRUNK - CSL DIFFUSER - AA SPORT TUNE - AA PULLEYS - BILSTEIN PSS9s - AS 40% SSK
CF CSL RACE LIP - NAVI - BMW PERF CF STRUT BAR - BMW GROUP N MNTS - GRUPPE M CF INTAKE - UUC SS BRAKELINES, TRANS MNTS, RTABs - 4.10 BMW M-SPORT DIFF