Great job Steve, I love the detail in the front compartment.
Done something, starting from the powerplant: we shared some ideas about the enine's parts fitting: looks like it's not perfect OOB: we guessed a solution may be cut and sand down all registration pins from each shell, glue parts (ex. cylinders) and carefully sand a bit the junction and scribe details with a PE saw. Looks like it work.
It's not so noticeable from the picts (also the engine is microscopic..) but I played with several Model Master Metalizer shades: alu for the block and cylinders, Alu followed by Magnesium and a light shade of steel for the gearbox (so buffing you'll expose a bit of the edge's alu

), steel for the carbs. I washed all a couple times with thinned acryl black; carbs were washed with a orange/pink shade (Lifecolor tensio-active).
(yep I know not so noticeable: I'll try to do better pict outside when the engine is finished)
Than I decided to play a bit. I decided to do few PE but at last I designed a good set to detail the Carrera a and B/C: this would be for sale then as quick as I'll try all parts and the service etch me first production sheets.
Obviously my TT partners would have my prototypes to use soon
Following the paper and metal mesh oval air filters, you'll see the interesting wing nut: those is MPWR copyright

, great idea buddy
And finally the very first fitting tests with carbs, fan cover and filters:
Parts are home made prototypes: I thrust pro etched PE I'll get would be better