I know this might sound like a stupid question, but what's a 'red top' engine? Is it the XE series, eg non-ecotec?
Still thinking of dropping a better engine in the astra, but heard that most 20xe's will probably be totally caned by now. Any other advice on any vaux. 2.0 16v that will be any good? (don't mind whether or not it's cat). What will I need extra-wise, as mine at the mo' is carburettored?