US Mercedes specialist Renntech has created a 144bhp upgrade for the Mercedes SL65 Black.

The ‘Renntech Performance Package 1’ uses a revised ECU, dual intercoolers for the bi-turbo V12 and a sports exhaust to boost the cars power output by 144bhp to 805bhp. Headlining the standard car’s stats was the fact it produced 1000Nm (that’s 738lb ft in old money), however the modifications now round the figures up to a nice, wholesome 1000lb ft (1356Nm). 

Obviously, deploying 1000lb ft to the tarmac via the rear wheels is easier said than done. To give the Renntech SL65 a fighting chance of not being overwhelmed by physics, Renntech has included a transmission upgrade in the package. A limited-slip diff with the ability to range from open to 100 per cent locked is deployed between the rear wheels to help keep the power in check.

VIDEO: Watch the standard SL65 tackle the Millbrook bowl at 180mph

Renntech are yet to provide any revised performance figures for the £10,700 upgrade (minus the diff), but as the SL65 Black was no slouch in stock trim, performance is likely to be ‘rapid’. Of course if you don't want to go to Renntech to have your SL65 tuned, you could always try Brabus.  

Read what happened when the SL65 met the mighty Aston Martin Vantage 600