I fitted one years ago, checked with my dealer first and they said it was OK to fit, wouldnt invalidate anything. Was still a bit concerned about reports of it providing more power than the CVT could handle. Only used it for a couple years then took it out because (a) still had that worry and (b) didnt really make that much difference to what my main concern.... which is - don't need more power, need more responsiveness from the sleepy CVT, pulling out is scary when the CVT does nothing for the first full second, except rev up and not move. But the sleepiness is a "built-in" feature courtesy of Subaru, it is programmatic and adaptive afaics. Because the TDI box made a short-term adjustment then the CVT adapted back to it's old "stupid mode" every time.
I have no idea where the "2 sec quicker" above came from, really doubt that is true, but anyway the CVT still wastes the first full second spinning about and "wondering what is going on" when you put the pedal down fast, so any gain is lost anyway.
However at 7 years in, many many years after I stopped using the box, my CVT blew up. Cost me many thousands to replace. No evidence it was the box but I strongly suspect it did some harm, while not giving me any increased responsiveness.
Overall for the gain vs the risks, I wouldn't recommend using one on a 1.6L.
I doutbt anyone would put it on a dyno and check, the 1.6L is so inherently asthmatic is not worth doing. However TDI Tuning seem like a professional outfit and I am sure they have actually put it on and measured the numbers in the lab, I believe their increased output claims, am just saying whatever you do to a Levorg in the *real world* to improve the drivetrain, the CVT programming will *always* defeat you. Period.
I have owned various performance Imprezas for 15 years before I got the Levorg 1.6, I do like driving it a lot, wouldnt swap it for something else, just find some things about it seriously flawed (sleepy CVT, terrible suspension, heavy self-centering steering with little feedback), have come to the conclusion it has been deliberately made so. Best thing to do is just to accept it's limitations.
I would love to import one of the Sportswagons from Australia, I hear they have improved some aspects of the above, and are inherently more powerful anyway which may be a bonus, but for me am happy with the 1.6 power, it is the need for the CVT to not be permanently in the wrong "gear" which matters most, no point in having power which doesnt arrive when you ask for it. e.g. you go into a corner with pace, put foot on the brake gently to adjust for the bend mid-way, then back on the gas mid bend to pull out fast and the dippy CVT has decided cos of the braking you are "slowing down to grab some shopping and a coffee, mid-bend", goes into the wrong gear position completely, then scrambles about for 2 secs to find out what is going on. The machine has absolutely no idea what is happening on the road. The "paddles" are absolutely no use, they do not control the CVT directly at all, they just say to the engine "I've put in a request for a gear change at your convenience, but feel free to blindly change the revs in the opposite direction at the same time so no actual power increase is provided, I mean we don't need that for the coffee-stop in the middle of this bend". Feels nothing like a manual and clutch whatsover, where you kick down the gear and get that torquey pull as you emerge.
Just need to get over it and accept being pressed then overtaken by a 800cc Peugeot 108 on a windy road, while yelling "sorry for the obstruction mate, this dipsy thing won't change gear".
Add to that the first bump you come to causes the whole suspension to wallow dangerously, followed by the smallest pothole which causes it to crash like you've just broken something.
And then the incredibly heavy self-centering "lets-copy-German-style-steering-instead-of-light-responsive-Japanese-steering" that doesn't actually want to corner.
The Levorg is designed for cruising along and occasionally a bit of pace, but nothing much else. Is pleasurable to drive doing that. But even overtaking can be frightening as when you floor it, the CVT does it's best to spin the other way ("to save fuel my dear, I know you are going to die in a head on collision from on-coming traffic because you cannot complete the manoeuvre, but don't worry at least you know you saved the planet 0.0001ml of fuel while you died").
It also seems to be a bit of pot luck. When my CVT got replaced with another unit from Subaru UK, the responsiveness of the car improved measurably (though still note all the above) and remained so till now (2 further years on). Did I get a dud the first time? Or is the programming all over the place? And yes, I did "reset" the previous one, it just learnt to be dipsy all over again each time.
Who knows. Have just learnt to live with "not really being in charge of the car/drive" any more. Needless to say the family all love it, just the driver is muttering away
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