try Nowack or Kellner-Sport both can tune an M3 to 400 hp, but it won't be cheap.
http://www.nowack-tuning.de/home1.htm and
http://www.kelleners-sport.com/engl/
here is what Nowack had to offer
Referring to your e-mail inquiry of February, 06th we would like to make the following offer free subject to alteration for the conversion of your car, BMW E46 / M3 SMG II model 2002:
NOWACK auto + sport ECU-tuning including v-max. de-limitation and rev.-limiter increased to 8.100 rpm.
power increase approx. 8 / 11 kw / hp *
torque increase approx 15 Nm *
price complete 1.535,-- €
NOWACK auto + sport engine-kit (EVO I), complete with:
NOWACK exclusive special sports-camshafts
optimization of air-intakes (RAM-air) and air flow
special free flow-air-filter
optimization of engine software including
v-max. de-limitation (v-max. > 250 km/h)
complete assembly
adjustment on our Dynojet chassis dyno including power test before and after the conversion
power: approx .268 kw / 365 hp
price: € 6.570,--
NOWACK auto + sport engine-kit (EVO II), complete with:
NOWACK exclusive special sports-camshafts
NOWACK exclusive special valve-springs
optimization of single throttle bodies
completely prepared cylinderhead (in- and outlets)
optimization of air-intakes (RAM-air) and air flow
special free flow-air-filter
optimized pistons
balanced crankshaft
balanced connecting rods, -polished-
NOWACK exclusive sports exhaust system (rear silencer), -stainless steel-
NOWACK exclusive headers
optimization of engine software including v-max. de-limitation (v-max. > 250 km/h)
complete assembly and adjustment on our Dynojet chassis dyno including power test before and after the conversion
power: 283 kw / 385 hp
max. torque: 380 - 385 Nm at 5.000 rpm.
price: € 10.180,--
NOWACK auto + sport N400 engine-kit (EVO III), complete with:
NOWACK exclusive special sports-camshafts
NOWACK exclusive special forged pistons
balanced crankshaft
balanced connecting rods with adapted weights, -polished-
completely prepared cylinderhead (in and outlets)
NOWACK exclusive special valve-springs
optimization of single throttle bodies
NOWACK exclusive complete sports exhaust system incl. stainless steel headers, high-performance motorsport catalytic converters, stainless steel rear silencer
optimization of air-intakes (RAM-air) and air flow
special sports-air-filter
optimization of engine software including v-max. de-limitation (v-max. > 250 km/h)
complete assembly and adjustment on our Dynojet chassis dyno including power measurement before and after the conversion
power: 297 kw / 404 hp
max. torque: 400 Nm at 5.200 rpm.
price: € 15.200,--
NOWACK high-efficiency brake-system M3, contents of:
Front axle:
2 x four piston aluminium calipers
2 x double-ventilated, holed brake discs (380 x 32 mm)
Rear axle:
2 x four piston aluminium calipers
2 x double-ventilated, holed brake discs (322 x 28 mm)
€ 9.780,--
assembly
€ 990,--
NOWACK light-alloy-wheels 19"
Front axle:
2 x 8J x 19 H2 offset 35
2 x tyres Yokohama AVS Sport, 235 / 35 ZR 19
Rear axle:
2 x 9J x 19 H2 offset 30
2 x tyres Yokohama AVS Sport, 265 / 30 ZR 19
€ 5.090,--
NOWACK special sports-chassis M3 -comfortable tuning- complete with
4 x NOWACK sports shock absorbers
4 x shorter NOWACK sports-springs with special NOWACK-setting
€ 1.990,--
electronic alignment
€ 125,--
assembly
€ 495,--
NOWACK special anti-roll-kit (front and rear axle)
€ 1.020,--
NOWACK speedometer
speedo 340 km/h
back light technology
€ 850,--
NOWACK rev. counter
yellow from 4.000 – 8.500 rpm.
red from 8.500 – 9.000 rpm.
back light technology
€ 850,--
All prices are Export prices, -net- , and do not include the legal German VAT (16%).
The maintenance after the conversion can still be carried out at every BMW workshop.
Conversion time: approximately 15 - 20 days
or: you'll buy a complete new, already prepared and dyno tested engine, we'll charge the amount for a standard M3 engine on top of the price for the conversion which we will re-transfer to your account after receiving your M3's standard engine.
To save money it is also possible that you first send your car's standard engine and we'll directly send a converted one to you. Then you'll just have to pay the price for the conversion.
Warranty: 1 year without kilometer limitation for the engine and electronics (for new cars and cars up to 30.000 Km)
Delivery time: the conversion can be carried out directly after placing your order / receiving your car in our workshop
payment: 50% when placing your order / 50% when picking up the car after the conversion