[Tycoon] Tech tree and R&D

So, I was making my '55 sportscar and was thinking to myself, why isn't there mechanical injection here? Mechanical injection was used during WW2 on planes and in '55 mercedes used it on the Gullwing. Then I remembered when someone made a aw11 replica and multi-point wasn't available and he had to use another year for the engine.
So I thought. These technical options should be unlocked either by R&D via a tech tree or both has components externally. For example, for the injection and carburettor components and the brakes.
Having a tech tree forces the players to specialize creating more identity to their brand and more options to make in term of investing you money. Do you invest in technology or prefer to buy the component some time after and for a cost higher than if you'll have research it.
Let me exemplify:
"I have to research all that crap to make a supercar with ceramic discs?" No, there should be a historical year when the research is made available(in cases where you need something external to make something, like electronic for the ABS) and another year for when the component becomes available on the market, either at the current game years for that or 2 years after the first player researched it.
Also instead of linear research you should have theoretical and practical research. If you don't dish out cars with the innovations you don't get practical.
So I thought. These technical options should be unlocked either by R&D via a tech tree or both has components externally. For example, for the injection and carburettor components and the brakes.
Having a tech tree forces the players to specialize creating more identity to their brand and more options to make in term of investing you money. Do you invest in technology or prefer to buy the component some time after and for a cost higher than if you'll have research it.
Let me exemplify:
............................../---->ABS--->Stability Control
Drum brakes--->solid disc--->vented discs--->ceramic discs
...............................\--->multiple pistons
"I have to research all that crap to make a supercar with ceramic discs?" No, there should be a historical year when the research is made available(in cases where you need something external to make something, like electronic for the ABS) and another year for when the component becomes available on the market, either at the current game years for that or 2 years after the first player researched it.
Also instead of linear research you should have theoretical and practical research. If you don't dish out cars with the innovations you don't get practical.