Yes, a Scottoiler is a must for any chain drive bike of you're gonna use it for commuting, especially over winter when you dont have time to lube the chain after EVERY ride!
Changing the gearing is a good idea as they dont make much use of their 130+ top end. Lowering the gearing makes it much more responsive at low revs (around town) and gives better acceleration. Just make sure you go up 2 or 3 teeth on the rear sprocket, as Anthony says don't drop to 14T on the front unless it's temporary as the tighter circumference will cause early chain wear. | 
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