There are no clips to hold in the 16v injectors, just the upper seals. The lower seals arnt as important, but it lookslike they got old n brittle and fell off. New upper seals all round would be my next port of call, possibly just fit a new set of brass ones just becasue they're cheap!
I'm not sure what the clips in the diagram were for, but not required. The 16v has 2 pumps, one under the car and another in the fuel tank, it does sound like the lift pump may have packed up. Get under the car and disconnect the wiring plug to the main pump, then turn the key 1 click so the fuel system primes. You should hear the lift pump in the tank, if not its dead
An 8v or 16v GTI lift pump will do, but the pre/post 90 pumps have different plugs, the lat ones have 4 pins & early only 3 iirc. Lift up the boot carpet and you'll see a round metal plate, remove this then check out which plug your pump has.
Main issue with swapping them is if you can undo the large plastic nut holding it in, in the end I had to cut mine off it was so tight! Not expensive from VW though.
