Bespoke Mercedes tuning specialist Brabus have done a bit of a lazy trade on the C63 AMG.Having seemingly expanded all its considerable technical resources in the guise of another C-Class performance project – the insane 537kW Bullit bi-turbo – last year, Brabus have now put forth a rather ‘soft’ C63 AMG upgrade.After a Bullit, everything else is…slow?When Brabus showcased the Bullit bi-turbo model at the Frankfurt motor show last year – just as the C63 AMG was being launched – there was an instinctive feeling regression was going to be the only way forward from a 537kW C-Class. How true this has proven to be too. Though Brabus claims to have extracted an extra 53kW from the venerable 6.2-litre AMG V8 via free-flow, high-performance metal catalysts, performance air filters and reprogrammed engine electronics, the truth behind the numbers is a little more revealing – and disappointing.Powerful for a C63, but not for a V8 AMGWith the Brabus tuning kit operational power increases to 390kW, and torque output is up only 20Nm to a new peak of 650Nm. These negligible improvements in engine performance drop the 0-100km/h sprint time from 4.5- to 4.1 seconds.A stock C63 AMG may only produce 336kW – the lowest output of all AMG fettled V8s – yet this is done not to upset the product planning detail of the AMG range. If the 6.2-litre V8 engine had not been detuned in the C63 AMG and produced 386kW – as it does in the S, SL and CL applications – it would seriously inhibit to purchasing appeal of these vastly more expensive models. Re-evaluate the Brabus power figures, and they’ve only rendered a 4kW improvement on a potential detuned, range-topping 6.2-litre V8 AMG engine. In the spectre of supercars 4kW is nothing, you could gain a similar performance advantage by simply dumping your passengers and blasting around alone to save weight. Revised suspension, huge stoppersThe rest of the Brabus conversion is typical autobahn storming detail. Tyres are 235/35 ZR 19 in front and 265/30 ZR 19 on the rear axle, mounted on multi-piece Monoblock VI, E or S light-alloy wheels unique to Brabus.Hiding behind the aggressively styled wheels are upgraded brakes, 380 x 37mm 12-piston callipered units at the front and with 360 x 28mm six-piston aluminium fixed callipered stoppers at the rear, with all discs vented and grooved for optimal performance. A key reason such high-performance brakes are onboard is the high top speed potential of the B63 S. You can have either a 300km/h or 315km/h speed restrictor calibrated to accommodate your zen for speed. Handling is bolstered by the presence of Brabus coil-over suspension featuring gas-pressure shocks with ten selectable settings for bound and rebound, which should hopefully enable you to find a single setting with a semblance of ride-quality; especially considering the standard C63’s atrocious ride comfort. If the Bullit bi-turbo V12 is too extreme - or expensive – for you this B63 S package should appeal strongly; by Brabus standards though, it’s rather tame.