Is this the ultimate Subaru BRZ?

I think I can see what's going on here: a game of spot the difference

Precisely, although as you might already know - or guess - most of the differences between these two cars are hidden underneath. We reviewed Litchfield's supercharged Subaru BRZ last week, and since it was around for a few days, we took the opportunity to get it together with our long-term BRZ for a back-to-back comparison.

Sounds sensible. Bet you want the supercharged one now though?

Yes, but it's not quite as black and white as you might think. For starters, there's a fallacy (held by lots of commenters on our first Litchfield review) that the standard BRZ is dog slow. It just isn't. Anyone else out there with a GT 86 or BRZ is welcome to corroborate this, but the more miles mine covers, the sweeter the engine gets. The odometer's just coming up on 10,000, and the flat four is an absolute honey. It sounds sweeter, it pulls harder, it revs moresmoothly. And it's not slow. Yes, it would take every ounce of muscle it has to keep up with a Fiesta ST or Golf GTI, but - and I'm going to bang the drum on this again - pure speed is not the be all and end all. It's how you and the car feel, the sensations you get. And what you get from the BRZ is this enthusiasm and eagerness to give all it has.

If you believe that, then why have the supercharged one at all?

Because I'm hopelessly inconsistent and quite like faster things? The key point is that the standard BRZ and GT 86 aren't as slow as people make out. The claimed 0-62mph time of 7.6 seconds is a fib - ours has gone almost a second faster. But the supercharged one is the next step on. No longer does the BRZ compete with base hot hatches - with Litchfield's £3,495 kit attached it has the pace to rival a Cayman S or Audi TT RS. But once again, it's not all about the straight line ability. The most frustrating thing about the standard BRZ isn't its lack of straight line speed, but the lack of grunt out of corners to really make the chassis work hard. There's real sparkle there, but not enough power to exploit it. The supercharged one has that muscle.

Doesn't that make it even more tail happy?

It does, but it's what happens up until the VSC stability control system gets involved that matters. You can feel the (admittedly grippier and fractionally wider) Michelin Pilot Super Sport rear tyres work harder, the chassis transferring weight rearwards, really digging in up to the point it can dig no more. Yet the engine still has more to give, so here you have three choices - keep your toe in and let the VSC deal with it; switch it off and cope with the slide yourself; or back off and work just within the car's limits, play with the throttle pedal. It's the last of these that's the most rewarding - not to mention the most socially acceptable.

So that's the fundamental difference between the two?

It all boils down to is the balance between power and grip. In the standard car it's very well judged and accessible, but occasionally leaves you wanting more. The supercharged one gives you the "more" you were missing. The balance tilts more towards power than grip, you have to concentrate harder, work a bit more, think about available grip. And no, it's not too grippy - the tyres are only 225-width.

What about the trade-off with ride comfort?

This is a harder one to judge, as the Litchfield's damper set-up hadn't been finalized when we drove it and was a bit harsh at low speeds. At high speeds you could tell the Bilstein shocks were worth the extra cost, but even so, there's less give in the Litchfield than the standard car, with its taller sidewalls and regular dampers. What lets both cars down is the amount of background noise that penetrates the cabin. That, more than the ride, is the real disturbance.

I do like the stance of the Litchfield

You're not the only one - the bigger 18-inch TSW wheels and the 30mm shorter springs have given the BRZ much more attitude. However, although they work a treat visually, they do add that bit more discomfort. It's a trade off you'd have to decide for yourself. Me? I think I might fit the lowering kit, but stick with 17s and use the taller sidewall. That said, those of you that read the magazine might recall I fitted a set of 18-inch OZ wheels to my BRZ for a few months (there's a pic in the gallery above). Combined with a set of Continental CSC5 tyres, the ride barely deteriorated at all. And blue and gold still looks right on a Subaru, doesn't it?

OK, back to where we came in, how much faster is the supercharged one?

Well, I conducted some very unscientific testing, the results of which are as follows: the standard BRZ will take 4.0 seconds to accelerate from 50-70 in third gear, the Litchfield, 2.8 seconds. A flat sprint from 30-70mph? 5.9 seconds in the standard car, 4.5 in the Litchfield. However, if you pop it in a big gear at low revs, there much less to choose between them - both posted identical 50-70mph times in sixth of 9.5 seconds. That's because Litchfield has used a centrifugal supercharger for the BRZ, which is smaller, lighter sand more efficient than a twin-screw design and requires less power from the engine to get it going in the first place. Not great for low down torque, but dandy once up and running.

Hmm, so what about a turbocharger?

There were loads of comments about GT 86s with turbos fitted when we ran the first drive on the Litchfield. As yet we can't comment because we haven't driven one. That, however, is something we hope to put right in the next couple of weeks...

So should I just order the Litchfield then?

Think twice before bunging every mod at your BRZ. I know it's tempting, but I'd really recommend getting your car's mileage into five figures before doing anything to it, due to the way it loosens up so well. And not just the engine, but the transmission, throttle, ride. Miles make a big difference. But yes, when all's said and done, I would quite like a supercharger.