Modified Mercedes A45 AMG for Sale in the UK
The Mercedes-AMG A45 is the most powerful production hot hatch to have been built around a 2.0-litre four-cylinder engine. Its M133 turbocharged engine — producing 360–381bhp depending on model year and specification — makes it a formidable performance car in standard form. Modified A45 AMG models take this already impressive baseline and push it significantly further, with stage 2 builds regularly exceeding 420–450bhp from the same compact package.
The aftermarket for the A45 AMG has grown considerably since the car's introduction, with specialist tuners offering ECU remaps, downpipe and intercooler upgrades, and gearbox software tuning. Stage 1 remaps on the M133 engine typically raise power to 400–420bhp, while full stage 2 builds with hardware support can produce 430–450bhp. The 4MATIC AWD system is retained through all stages of tune, providing exceptional traction in all conditions.
Modified A45 AMGs in the UK often feature custom exhaust systems designed to enhance the car's signature AMG soundtrack, including the pops and crackles on overrun that have become part of AMG's modern identity. Suspension upgrades, brake enhancements and styling modifications are also common, with the A45's aggressive factory styling lending itself well to further aerodynamic additions.
On Madlows, you'll find enthusiast-owned modified Mercedes A45 AMG models for sale across the UK. Browse listings with full modification details and verified seller information to find your ideal tuned A45.
Modified Mercedes A45 AMG Listings
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List your A45 AMG todayPopular Mercedes A45 AMG Modifications
The M133 engine responds well to tuning, with a growing aftermarket supporting significant power increases. Below are the most popular upgrades on modified A45 AMG models.
Engine & Performance
- • Stage 1 M133 remap (400–420bhp)
- • Stage 2 with downpipe & intercooler (420–450bhp)
- • Fuelling upgrades for 470–500bhp+
- • 7G-DCT gearbox software tuning
- • Performance exhaust systems (Milltek, Akrapovic)
- • Custom pops & bangs exhaust maps
Chassis & Styling
- • Coilover suspension upgrades (KW, Bilstein)
- • Big brake kit upgrades (AP Racing, Brembo)
- • AMG aerodynamic upgrades and body styling
- • AWD servicing and differential upgrades
- • Lightweight alloy wheel upgrades
- • Splitters and rear diffuser additions
Mercedes A45 AMG Buyer's Guide
When buying a modified A45 AMG, these checks will help you assess the build and anticipate ongoing costs.
M133 Oil Change History
The M133 engine requires regular oil changes with quality oil meeting Mercedes-Benz specifications. On tuned examples producing 400bhp or more, oil change intervals should be shortened to every 5,000–6,000 miles. Ask for a full service history and check that the correct grade of oil has been used — the M133 is sensitive to oil quality, and deviating from specification can accelerate engine wear.
Gearbox Condition
The 7G-DCT dual-clutch gearbox is generally a strong unit, but requires regular fluid changes — particularly on tuned examples. Listen for any juddering at low speeds or hesitation during gear changes, which can indicate clutch wear or low fluid levels. Ask for evidence of gearbox fluid services and confirm the gearbox is shifting cleanly and without issues before committing to a purchase.
AWD System & Running Costs
The 4MATIC AWD system is generally reliable but should be checked for any binding, vibration or clunking during low-speed manoeuvring, which can indicate issues with the Haldex unit or driveshaft components. Budget realistically for the higher running costs associated with AMG ownership — service parts, tyres and insurance are all typically more expensive than equivalent VW Group alternatives.
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Frequently Asked Questions — Modified Mercedes A45 AMG
How much power can a modified Mercedes A45 AMG make?
The Mercedes A45 AMG uses the M133 2.0-litre turbocharged four-cylinder engine producing 360–381bhp in standard form (depending on specification and year). A stage 1 remap typically raises power to 400–420bhp. Stage 2 builds with a full downpipe, upgraded intercooler and intake commonly produce 420–450bhp. More extensive builds with fuelling upgrades and hybrid turbo conversions can push beyond 480–500bhp. The AWD system handles increased power levels well, making the A45 a formidable all-weather performance car at any stage of tune.
What gearbox tuning is available for the Mercedes A45 AMG?
The A45 AMG uses a seven-speed dual-clutch transmission (7G-DCT). Gearbox tuning software is available from specialists and can improve shift speed, launch control aggressiveness and overall gearbox response. The 7G-DCT is generally considered a strong unit that handles the M133's power well, though regular fluid changes are important, particularly on tuned examples. Some owners report that the factory launch control strategy benefits from recalibration to make full use of the car's 4MATIC AWD system at higher power levels.
Are modified Mercedes A45 AMGs expensive to maintain?
The A45 AMG has relatively high maintenance costs compared to similarly powered VW Group alternatives. Mercedes genuine parts carry a premium, and specialist AMG-qualified mechanics charge accordingly. Key maintenance items on tuned examples include regular oil changes with quality oil (the M133 is sensitive to oil grade and change intervals), gearbox fluid changes, and monitoring the cooling system on stage 2 and above builds. Insurance is also typically higher than for equivalent VW Group performance cars due to the AMG badge and higher standard power output.