Bostig alloy one , demon performance alloy one , pumaspeed alloy one .
The silver top one isn't that bad compared to the blacktop one that's really shit as I found on my st170 ended up using a uprated one off another model ford that's made from same material as the early silver top ones from cfm in America, been fine since fitted. You could also get an alloy that came fitted toearlyzetecs as standard there was one on eBay last week it sold for around £ 46
Hope this helps

Cheers paul