A fair bit of potential in this episode, but as others have noted, it's let down by a failure to execute. Maybe they're trying to pack too much content into the allotted time, but everything always seems rushed (with the exception of SSIARCC, which is too long). Still, I liked it more than the previous three, overall.
Evans seemed to have dialed it down to 11 this week, which was welcomed. And Sabine also stopped shouting most of her lines (I still find her quite understandable), though her laugh is grating. Matt does seem terribly bored with all his delivery - maybe he's actively trying to counter Evans' shouty delivery.
As to the bits:
Race to Venice: As noted, far too short - should have been about twice as long to really work. These don't need to take up the majority of the show's runnning time (as I recall, the original race to Monte Carlo was completed by mid-point of the broadcast), but they need more than 15 minutes. They didn't talk much at all about their cars nor about the Orient Express (which is an amazing train even today). I thought Eddie was actually probably the right choice to send on the train, though instead of the stupid "serenade of spoons", spend that time talking about the train and it's history.
AM Vulcan Review: If Harris is channeling Clarkson, he's doing a good job because I thought it was a solid, proper TG supercar review. If anything, it was a better review from a technical and mechanical basis than what Clarkson would have done as Harris focused more on the car than on being witty (mind you, I love Clarkson for his wit). As to being the best on-track film ever, sorry, but no. It was well-done, but the crew did it better on the same track with Hammond and the Porsche 918 Spider last year (?) and I'd put Jeremy's run in the McLaren P1 in the rain at Spa as #2 (just for the audacity of it). Mind you, the Vulcan's exhaust echoing off Yas Marina was the sexiest sound ever in terms of automobilia.
Tesla X Review: Actually saw one in the flesh last week and it looks better in person than on TV (the one I saw was in red, which no doubt helped, as well). Reid is not as polished as Harris, but he comes across as honest and ethusiastic and I respect that. I also like his behind-the-scenes segments about the filmings on Extra Gear.
SSIARCC: Best part of the episode was the announcement Brian Cox has another BBC series coming (I love the "Wonders of..." series). In terms of running time, while it does feel like forever and a day, is it honestly longer than the segments where Clarkson interviewed two guests at a time? As I have noted before, let the guests talk about their projects themselves - it should take less time and be more enthusiastic. Then cut the first and best cars segment, instead spending half that time talking to the guests about themselves or their current product pitch and then do the laps. Add the time saved back into the other content.