Technical director James Key admitted that the major differences between this year's machine and its predecessor are currently on the mechanical side, but that some fundamental concepts are being worked on for introduction later in the season.
Some of these parts will appear during pre-season testing, but major packages are planned once the season is underway.
"We have got some bits coming for the next test and the test after which will visibly change the car," said Key.
"We are working now on the future steps and we will evolve.
"We're already looking at different types of approaches in some areas, fundamentally different approaches that will eventually come to life later in the season."
Despite the relatively conservative aerodynamic step, Key is confident that the major leaps forward on the mechanical side will allow STR to improve at the start of the season.
"Mechanically is probably the best step that we've made even though aerodynamically it's immature," said Key.
"That, combined with the new tyres we've got, we have got pretty good opportunity of getting quite a bit more out of it.
"The suspension packaging and the way the suspension works is very different. It will open up a lot of things that we can do with this car that we couldn't do with STR7."
Key also explained the reasoning behind the team dropping the aggressive 'twin floor' design concept that it has used for the past two years, which is the one major changes to the car aerodynamically.
While the STR8 features an aggressive sidepod undercut, it was decided to follow the design trend favoured by its rival teams in recent years.
"We were the only team that was doing it," said Key. "I looked at it with my previous team and you could see what was going on, but it wasn't an obvious step change.
"We had the capacity to change it on this car, which was designed to allow us to go lower with the coolers and fill in that gap and we decided to go with it.
"What we saw with the STR7 was that it was drying up a bit and getting difficult to find more on the aero side, so making a step changes encourages new development directions."
F1 editor Edd Straw
When team principal Franz Tost declared that Scuderia Toro Rosso's target for the 2013 season was to finish sixth in the constructors' championship, matching the achievement of the near-miraculous 2008 season when Sebastian Vettel claimed the team's sole victory, it was difficult not to be sceptical.
Last year, Toro Rosso finished ninth, 100 points behind sixth-placed Sauber and spent a decent proportion of the season firmly rooted to the back of the midfield pack. The team directly ahead of it - Williams - won a race on merit, just to underline just how big a step Toro Rosso needs to take.
Effectively, it needs to beat all of the teams that it realistically has the potential to. While things took a turn for the better in the final third of last season with regular points finishes, that's still a big gap to bridge.
There are some reasons to take it seriously, even if beating all of Williams, Sauber and Force India is a long shot. In James Key, it has a technical director with a proven track record after turning Sauber back into top half-dozen material.
His approach seems logical. Key grew up in Formula 1 working on the vehicle dynamics side at Jordan and the mechanical changes STR has made reflect his clear ideas of how to get the best out of the car and the tyres. The team is confident, therefore, that the far wider set-up window will automatically buy it some more points over last year.
One of the reasons why Giorgio Ascanelli was not looked upon as the future by the team's ownership was that the aerodynamic department working under him wasn't making as much progress as required. Cue a series of personnel changes, which inevitably has led to a certain lag between new blood coming in and the fruits of their labour.
When Key says to expect some major aerodynamic changes, there's every reason to believe him. It might not be until the start of the European season, or even later, that we see the true 2013 STR.
All of that might not add up to sixth place. But it will certainly equal a team on an upward trajectory, and that in itself is more important than achieving an arbitrary position in the constructors' championship.
Toro Rosso STR8 - full coverage:
Toro Rosso reveals its 2013 car
Toro Rosso STR8 in pictures
STR: Team not drivers under pressure
Analysis: STR aims high with new car