If you're fitting greys, I'm guessing its a 380bhp+ engine.

Personally if I wasn't 100% sure about what I was doing, I would bite the bullet and spend a few squids and travel a few miles to get it done by a pro.

If running greys there is probably a good few quid sunk into the engine, plus if it was my mate I'd worry about something me messing something up, or damaging the injector causing a melt down.....

If it was a straight job and looked how the picture said, then fine, but it looks like it's not. Hope it all works out - but IMO could end up with a rebuild, hence the comment.....