What oil for Mk1 1.8 with 100,000 miles and planned track / fast road use

HI

I have just purchased a 1.8 Mk1 with about 100,000 miles on the clock. Car going to be used for fast road and track use (about 50/50) and it needs an oil and filter change

What type oil would be best? I usually use sythentic in my cars but sure i have read before that higher mileage engines usually demand semi synths etc. Is this right? If synth what weight / grade would be best?

Matt

 You don’t NEED to use full synthetic, but it won’t do any harm, except to your wallet. A good semi-synthetic, 10W-40 will do nicely, I would recomment changing it every 4~5000 miles, or twice a year, whichever comes first.
One thing I really would recommend is the use of either genuine Mazda or ‘BLUPRINT’ filters, definitely not Fram (according to US users). I always use the filter for the Mazda MX6 (or 2.5L Ford Probe) as it has about 30% more capacity but the same internal structure/size.

 Silkolene Pro-S 5W-40, fully synthetic. Good quality stuff.