Couple of points here....
The injectors are unnecessarily mounted too far away from the manifold, meaning injector pipe runs are unnecessarily long. The injectors are of a design that should be mounted vertically but are mounted horizontal. You could kill two birds with one stone by mounting the injectors at the side of the engine, this would be made easier using side exit injectors like OMVL's. The reducer seems to be mounted upside down on the pic, not a problem but will arguably make servicing more difficult. The reducer is also possibly capable of swivelling unless those holding bolts are very tight.. We can see the 30 degree toroidal tank's vent tube but it doesn't protrude quite protrude enough through the boot floor. The boot floor doesn't seem to have been painted after the hole was made. The Valtek injectors will have 4mm OD nozzles but you fitted DN5 (5mm) injector hose (Eagle eyes here tonight lol). Why fit a 90 degree filler then use a 90 degree fitting after the filler when you could have fitted a straight filler that would have been neater, less chance of a leak between fittings, cost less, been neater and allowed a faster fill? if you're going to paint the filler fitting, why not paint the cap at the same time? How did you paint the cap? Really it needs smoothing down (they have rough edges as they come), plastic priming, painting, laquering if metallic. Takes ages to properly colour code a filler otherwise the paint comes off very quickly!
With the way the air box is designed and the resination chamber, it would mean making spacers to raise the air box up, would also have to make the inlet pipe from throttle body to air box from silicone hose if i did it like that. The pipe from throttle body to air box won't flex as much as you think it's already tight at the minute to clear the injector pipes.
I couldn't mount the rail on the side as it would either the A/C pipes be in the way on the right side, the left side of the engine has the abs modulator and Aux belt so would be a pain for servicing thats why i chose there where to mount it up, If the rails get sticky i will make a spacer so the rail can be on a 45 degree angle instead of just being mounted horizontal. The way the regulator is mounted is so the solenoid can be accessed easily for servicing it's not to bad tbh. Yeah the bolt is tight on the reducer it goes through a captive chassis nut and a nylock nut is on the back of it to keep it tight.
It's on a double skin you have the boot floor and then a seperate skin mounting a towing bracket to it will get some better pics over the weekend. It protudes through about 3-4mm if it's too short i will fit another as ive not yet sika-flexed the vent pipe in yet. I was looking at fitting 4mm but it always seems abit to small for my liking don't now why but just prefer 5mm, it's a nice snug fit on the injector pipes to injection rail, you can't pull them off you need to release the clips.
The filler hasn't been painted just in the standard black as you get it, as it matches the black exterior trim on the vehicle already, and the fillers look @!## if not sprayed well and if you don't use plastic primer or plasti-cizer in the paint it flakes of after awhile i found.
Over the 90degree filler i got was i wasnt sure where i was going to run the lpg pipe and i was alittle unsure on fitting as there is a steel panel a couple of inches away from the pipe so wasnt to sure but can be changed to a straight 8mm fitting at a later date if wanted as ive got some in the toolbox.
I will get some pics of the pipe running front to the back and see what you think simon, i had a hard time trying to find chassis points as per the rules say, had to use the floorpan to secure some of the fixings (Does say in the regs i think on this)