FAST

FACTS

Buyers who wanted the ultimate M5 while still retaining the factory warranty would turn to Dinan, whose highest performing offerings include the S2 (shown here) and a few years later, the S3 (supercharged)
For the S2, Dinan chose to maintain the spirit of the M5 by keeping it naturally aspirated. Output was bumped by 76 horsepower, and a shorter final drive (3.45 vs 3.15) combined with a slightly higher redline made the S2 feel substantially faster than a regular M5 on the top end
The S2 package focuses exclusively on engine breathing to create power – no internal engine modifications here. Carbon fiber air intakes, high flow MAFs, and bored-out throttle bodies with shorter, larger-diameter velocity stacks
The S2 exhaust weighs 29 lbs less than stock and features Dinan’s bespoke 4:2:1 anti-version headers. Advertised as being made “with the finest materials”, these headers alone retailed for nearly $8k
It took Dinan 2 years to reverse-engineer the BMW ECU and create their own code, referred to as their “Stage 6” software
The suspension is fully upgraded to Dinan’s Stage 2 system, which is intended to maintain the balanced handling the M5 is known for: slightly stiffer Koni adjustable shocks, performance lowering springs, stiffer sway bars, and strut/shock tower braces. Period road tests report there is little change in ride quality compared to the stock M5, yet skidpad grip increases from 0.83 g to 0.87 g
As a small but significant touch, Dinan takes the factory dual-mass flywheel and removes 7lbs. By eliminating the weight in the appropriate areas of the flywheel, rotational inertia is reduced by 40%. Car and Driver proclaimed “easier clutch engagement”, saying that it was actually easier to take off smoothly compared to the stock clutch
The S2 package also includes a 3.45 LSD and an upgraded aluminum radiator to replace the (inadequate) factory plastic unit. A set of Dinan’s “Champion” forged lightweight wheels are wider than stock yet weigh only 18 lbs each
While the S62 V8 is based off the 540i’s M62 V8, BMW claims the engines are 95% different. For the S62, VANOS was added to all four camshafts (vs only two on the 540i), and as a safety net, a double roller timing chain replaced the M62’s single-row chain. The more robust setup means the M5 is less prone to plastic timing chain guide failure than the 540i

Key Model Year Changes:

2003 updates:
Rear side airbags and a split-folding rear seat is now standard (September 2002 build date and onward)
Very few changes were made on 2003 models as the E39 generation was phased out for the E60
The M5 was the only E39 that could be optioned with an electric glass moonroof. All other E39 models could only be had with a sunroof. M5’s came mostly fully equipped – there were only a few options available from the factory. Some of the standard equipment could be deleted, such as the rear spoiler and “shadowline” trim

Specs:

5.0L V8 (N/A) (S62)	6spd manual (Getrag 420G)
470 hp @ 6900 RPM	419 lb/ft torque @ 5000 RPM
0-60 MPH: 4.1 sec	Top Speed: 191 MPH
Base Price in 2003:	$70,400+ Dinan package