A 27mm deep socket and a ratchet should break them loose, the injectors on my 300D weren't hard to get off at all.

__________________
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1973 450SEL 119,200 miles

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles