Hi everyone, first post and just wanted to applaud you on this amazing idea, I missed the old days of Car Tycoon and this lead me to your site. Car guy since birth and that’s why I got into the MechEng by trade, but since it looks like you have amazing progress with the technical side of the game I thought I would ask some questions/make suggestions for the business side (my other hobby trade 
). Spent hours reading through all your info so hope I don’t repost questions!
Reward
One of the important aspects of tycoons is the reward part of the game – spend hours designing an amazing car and I want to see it driving around the streets! So are there plans for how you will see your cars being driven around? At car shows? Being produced at your factories? Lined up on the dealer lots? Being driven off the lot? Go to a racetrack and see customers racing your cars? The better your company does the more you see your cars on the streets type thing.
Market Segment Criteria
I am sure you can’t divulge too much about your buying engine, but are the criteria customized for market segments? Ie. Sedan buyers want room and trunk space, truck buyers want towing and load capacity, sports car buyers want performance, etc. This also relates to the design criteria used for each segment. Will there be a way for the user to get feedback from the market? Say what cars are hot or what things the public likes/dislikes about your car?
Brand Image
Customize company names? Logos? Marketing materials? Maybe too much detail here, just speaking my mind. If the user is able to upload their own emblem art and that gets used on the cars that would be neat. Also going back to having cars roaming the streets – in Car Tycoon you can tell your cars apart by colour. I assume in this game you would want multiple colours of your cars to be sold – so maybe there are pop up (“speech bubbles”) that follow the cars as you hover the mouse to see what they are. Emblem could be used here too.
Model Years
Like the real world consumers love the latest and greatest and older models typically sell poorly among the new cars with all the new bells and whistles. So will cars have models years? Will you be able to make model refreshes? Will the age of the design factor into how much the public wants to buy it? Maybe brand loyalty will pay off and consumers will continue to buy your cars longer.
Model Unveiling
Part of the marketing section I guess, maybe you could setup different events to unveil new models?
Sub Brands and Company Shares
Not sure how the ownership of the different companies works. Will you be able to buy out other companies and either kill their brand or rebrand or have them as a subsidiary? Or potentially just purchase controlling stake in other brands/companies? Will you be able to rebrand the same car and sell it under two of your company sub-brands? Maybe not the best business decision but certainly has been done in the real world. Will brand loyalty be different in different regions? If your company HQ is one region will it affect your loyalty in that region? – Maybe I am going into too much detail.
Company Advisers
This idea is from the Sim City games, where you have city advisers for different aspects of running a town. In this case it would be company advisers for different departments that give hints or ideas or potentially provide the required information to make decisions. Example: finance adviser, production adviser, marketing adviser, engineering/design manager, board of directors adviser, supply chain adviser, dealer network adviser, etc.
MSRP
So will the user be able to set the sale price of each car? If so will there be a summary of the cost to manufacture the model and how the MSRP will impact the margin made on the sale? To that effect are prices set differently per region? Does the user have anyway of researching or getting information about different markets, like average sale prices or other info.
Misc Design Items
I think a few people have touched on stereos and interior design options. I think this would be a great addition to the game and be able players to produce different trim levels. Also it adds a level of profit margins to the game for the business side of things. Example: base models won’t have the profit margin as say the “Titanium Premium Limited Trim”. Other misc design details could be like paint and colour options, wheels, or perhaps limited production runs (ie only 1000 of this model will be sold).
I guess that is it for now. There are probably too many open ended questions to be easily answered but hope it helps the design process. Keep up the great work and all the best to make this happen!