The most important place to spend money is the tires.
They are your ONLY contact to the road ... all of your stopping power, and leaning/turning/swerving abilities come from the RUBBER.
It is THE weak link of the bike. Please please do not cheap out on tires.
That said ... I also have a cl350... wider rear tires are important when the bike has enough power to spin out ... yours does not... so going wider than 3.5 is pure aesthetic and not functional...
... in the front narrower is again better as it's far less sprung weight but more importantly easier to turn.
Stock rims are 1.6" rim with 3 inch rubber front and 1.85 inch rim with 3.5 inch rubber rear.
Please pay attention to this chart showing the standard and safe widths of rubber to rim. A super wide rubber on a thin rim is asking for death by pothole...
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