Basic improvement would be that the motor is about3-4mm to short and the cylinder banks are not offset I cut the block and heads & covers in half crossways and inserted stock (angle is wrong but that can't be seen from above. The air filter is totally wrong and would need a new top scratching to get it something like the real thing. I thought it sits too low too so lifting it a little can help fill the void. Air filter and carb and water pump are the major visible improvements if you only have the one hatch open. The engine really is diabolical compared other trumpeter offerings.
Thanks, any pics of your engine mods? The issues you mention about the engine are the ones I was speaking of in my first post.