yea more than enough mate (2,5-3 inch is fine as well), just make sure to go for a turbo back since the restriction in flow in the d22 is on the dump pipe. thats why cat back systems dont work that well (except sound of course)
2.75 inch system seems to be the go for the 2.5 litre diesels. fitting a 3 inch dump pipe at turbo end is a very tight fit between the pipe manilfold end and the cars firewall.
Its not physically possible to have a 3" dump straight out of the turbo...most a butchered down to about 2.5" to get a 90' flat bend then go to 3" after that.