wire ringing won't cost anywhere near £400 either,i'd expect £150 at the most.

the idea is to increase the sealing of the fire rings on a standard or group A gasket (fibrous type)to prevent them blowing out,
a 205 block in a 2wd car would be fine for decent power,mines working fine at over 400bhp anyway.

The 200 production blocks aren't that much better than a 205 really,but they are slightly better,so i'd use one and keep one spare

a WRC headgasket would be better than Wire ringing also,but at £370 ish they are a little dear,but they are fit and forget (provided they are fitted to perfectly flat surfaces)