3000 mi Royal Purple

 

3750, using Mobil 1.

 

Unless you are doing things like short trips(<8-10 miles/journey , lots of idling, or lots of cold starts there should be no reason not to go 7-10k per change or meven double that if you change your filter only.
To change a good quality synthetic early, is wasting $$ and you likely would do as well sticking to a good dyno oil.
If you're concerned, then do an analysis every 3K and see if there are problems, actually analysis is a good thing anyway once and a while to tell if there is any unexpected wear.
Search the net for oil analysis. There are several good ones out there (Analysists is one). It will cost ($20-30) bucks/test but it will give you some confidence.

 

5 to 7k, Royal Purple

 

Every 3,000 miles...Redline

 

I'm doing 3750, too. Halfway between my stops at the dealer for the official service.

 

I've read on this board that the wheel size on the S2000 must be larger in Back than front otherwise the resulting Handling could be dangerous.
You may want to look into that.

 

You might want to consider oil analysis with extended oil changes. I've spent years changing my oil once a year using Mobil1 (changing filters every 5k miles) but decided to be more scientific this time around since this car's a keeper. Check out this thread for more details and a copy of my latest analysis...

 

6,000 miles between, currently 45,000 miles total.

 

I'm thinking about changing my oil every other time I start the car.. I mean what does Amsoil know with their 25,000 mile oil life change... heck all they are is the professionals in the business and wouldn't know anything more than I would..

but seriously, I change mine at the oil life mark.. using Mobil 1(will start using Amsoil now that I've found a place that sells it for not much more than Mobil1)