Tesla's (TSLA -2.71%) most important vehicle launch ever is now just over a week away. On Friday, July 28, the electric-car maker will fully unveil its Model 3. Tesla expects the $35,000 vehicle to serve as a major catalyst for the company, driving annual production up fivefold by the end of next year.

But with the Model 3's final unveiling just days away, many of the most important details about the vehicle are still shrouded in mystery. Here's what investors should watch for at Tesla's event next week.

Model 3 prototype at Tesla's Gigafactory in Nevada

Model 3 prototype outside of Tesla's Gigafactory. Image source: author.

Range

Perhaps the biggest question going into the Model 3's official launch is what its driving range will be on a single charge. So far, Tesla has only said that the range on the base Model S version will be 215 miles or more. But at Tesla's first (and very limited) unveiling of the Model 3 last year, CEO Elon Musk was clear that the data presented for the vehicle represented the floor of what's possible for Model 3. 

"I want to emphasize these are minimum numbers. We hope to exceed them," Musk said.

For comparison, General Motors' (GM -0.07%) recently launched all-electric Bolt, which has a starting price of $37,500, can drive 238 miles on its 60 kilowatt-hour battery. Of course, the Bolt is more compact than Tesla's Model 3, but as the only other all-electric vehicle with over 200 miles of range selling around the same price point, the Bolt serves as an excellent point of comparison. Indeed, the Model 3's range may be of interest to not just Tesla investors, but General Motors investors as well.

Supercharging

Another key point to look for is whether Model 3 owners will be allotted a certain amount of free charging every year. Last November, Tesla said it would soon begin making its Model S and Model X customers pay small fees for using its fast-charging network. But the fees would only be incurred after 400 kWh of free charging every year (roughly 1,000 miles).

Will Model 3 owners also get 400 kWh of free charging at Tesla's Supercharger network every year? Or will this perk be reserved for Tesla's higher-priced Model S and Model X?

Autopilot pricing

Importantly, Tesla has already said its second-generation Autopilot hardware will be included as standard equipment in every Model 3 sold. But customers will have to pay to activate Autopilot, just as customers must for Tesla's Model S and Model X.

The question is how much Tesla charges Model 3 customers to upgrade to its "Enhanced Autopilot" or Tesla's yet-to-be-released self-driving capability, which Tesla lets its customers pay for in advance of its eventual launch?

Currently, Model S and X customers can enable Enhanced Autopilot for $5,000 if active before delivery. After delivery, it costs $6,000. Purchasing Tesla's "Full Self-Driving Capability" ahead of its release costs $3,000 before delivery and $3,000 after delivery, on top of an Enhanced Autopilot purchase. Will Autopilot pricing be the same for Model 3?

Vehicle production at Tesla's Fremont factory.

Tesla vehicle production. Image source: author.

Production plans

Finally, investors may want to look for an update on Tesla's production and delivery expectations. Planning to deliver about 30 Model 3s at its handover event next Friday, Tesla will undoubtedly have more vision into its expected production trajectory.

Earlier this month, Tesla said it expected to deliver about 30 Model 3s at its launch event, approximately 100 in August, deliver above 1,500 in September, and reach 20,000 Model 3s by December. 

Investors should look for Tesla to maintain this guidance for the Model 3's production ramp-up next Friday.

Whatever Tesla shares about Model 3, investors will probably benefit from tuning in.