Injector Rail change, worth a go?

1998 golf 1.4 idling issue, failed MOT on high emissions, but passed now, still idling, was smoking, but smoke has stopped. Broke down last week 220 miles from home, RAC decided to repair at thier own garage as it was too expensive to tow, the thermostat had gone & a hose pipe of some sort. They changed it for Free, nice.

Anyway car still idles funny in standing, when starting etc. I bought an injector rail of ebay, is it straight forward to change it, 2 screws and a hose pipe. Presumably there is petrol that goes in the injectors, will have have a starting problem after changing injector rail due to fuel not following through or something. Is it worth changing it? Will i need to disconnect battery first i guess.

you will probably need to disconnect the fuel pump relay, and crank it over before you disconnect the battery to relieve the pressure in the fuel system (before you disconnect anything fuel wise)