This is a highly modified JCW Cooper S spotted in mid 2024. Asking price was over $20k at the time. The seller noted the following commments about the car in the original advertisement: 

R53 JCW 210 (JCW210 options: JCW AirBox, Stainless exhaust system and cat , JCW Cylinder head, larger front brakes 12 % pulley) plus: Further modified with a 17%pulley, GP Intercooler, Ohlins road and track front and rear, Alloy rear arms, Whiteline rear sway bar, JCW head modified by Thumper to TPR2 spec (Fully ported and pocketed with larger valves) with matched intake, Scorpion high flow manifold and race cat (also have decat pipe), runs the later VDO MS5150 ECU with Bytetronic, 550 injectors, hi flow Lohen fuel pump new regs etc, Supercharger is the later coated type with perfect rotors - just serviced with new water pump and alloy stat housing, BMW Rear Seat Delete insert, factory Sparco JCW leather seats, TTV lightweight flywheel, TTV organic clutch and TTV lightweight pressure plate and Quaife diff and Newman PH2 cam. Makes and easy 260bhp 190ft/lbs crank at 18psi boost. Aero kit (very rare). Everything’s been done on this car and it flies along. Makes an easy 260bhp flywheel and 190ft lbs. Some of the mod costs: GP Intercooler - $1000.00 (Best Intercooler - Very rare). Ohlins Road and Track - $3800 (From Pro-Speed). R56/GP Rear Alloy Arms - $1000 (Fitted with new bushes etc). TPR2 Head Mods to JCW - $3000 (Thumper $2000 USD). Ported Inlet Manifold - $600 (Thumper $400 USD). Scorpion Exhaust Manifold - $2000 (800 GBP with decat + shipping). TTV Flywheel & Clutch - $2500 (1290 GBP + shipping) Quaife Diff $2000 (798 GBP + shipping). Newman Cam 250/400 PH2. $500.00 (220 GBP + shipping) Bytetronic MS5150 ECU $1000.00 (USD 750.00) Bytetronic Full Access Kit $1000.00 (USD 649.00) TOTAL $18400.00 TPR-2 Head spec: - Int. +.5mm Valves
 - Exh +1.5mm Inconel Valves - Ported Intake & Exhaust - Roof re-shaped - Throat & Bowl Pocket Ported - runner cross section opened & corrceted - Performance Valve Job w/ Flow-cut - Custom steel Valve Locks - Titanium Retainers - Custom Bronzamium Guides - Custom Steel Valve Locks - Racing PAC Performance Valve Springs - Max suggested 7800 RPM All mods done in the last 20,000kms.

Not quite factory, but 260+HP is an incredible figure from a 1.6!