You don't have to run full synthetic even if you do race the car or rev it up high. Non-synthetic can be just as good for an S2000 in any kind of driving.
In Canadian type of driving scenarios, you should be changing the oil every 5000 KMs regardless of the type of oil you use. I have always used synthetic and still changed mine at 5K KMs intervals just because of the harsh conditions of Canadian climate under which I operate the car. An oil change is one of the cheapest forms of insurance and some may say that you can "over-change" your oil, but 5000 KMs can not be consider changing too often (IMO for our climate).
Go with 5W30 for winter and 10W30 in summer in a non-syn for both and you'll be fine.

What do you mean by "wrong" filter? The "approved" filter from Honda is the PCX type, however, I've never used a Honda filter in the 5 years I've owned the S. I've been using Purolator and Purolator PURE ONE filters and my car's oil analysis have come out just fine. Just make sure that if you go with aftermarket filters, you pick a name brand in the correct model for the car. The kind of driving you do, you shouldn't need to worry about having the "BEST" filter money can buy. K&N and Mobil 1 filters intended for an S2000 are also good.

 

When my car was still under warranty, my local honda dealer used 5-40 oil. No I am doing my oil change and use Shell Helix Ultra 5-40

Min temp in winter is around 42F
Max temp in summer is around 100F

Should i change to 10-30 now that i am FI ?

 

Given this temperature range, I think you're fine with what you are using. In fact, if I could easily get it, I'd use it all year round myself.

 

 

Canadian Tire carries Castrol Syntec 5W40. It's the European formula that is PAO group IV, not the hydro-cracked group III stuff. It's the same price as Mobil 1.

 

I need to pay attention more when I go to Crapy Tire. I usually buy my Mobil 1 from Wallmart. (No 5W40 syn. there)

 

Haha...I go to Walmart most of the time too...it's cheaper. I'm surprised Crapy Tire is still in business since Walmart came to town!

 

But Crappy Tire sells fairly decent tools now. Not like in the old days, when EVERYTHING they sold was crap.