how much should I sell for ? F56 Cooper

as title, just offered to a friend right now but think I've underpriced considerably based upon auto trader prices, trade suggests just under £7k, which seems a bit of a nonsense when similar are listed nearer £10K,
appreciate I have modified from the norm which makes it less attractive for some, but would welcome opinions

purchased from original owner 2018, Dec 14 mini cooper f56 in black, just under 40k miles, I am 2nd owner, full service history
taxed and mot's last week, small chip on windscreen and apparently a loud exhaust :)

original extras
electronic aircon
mini driving modes
visual boost
chilli pack
half leather tartan interior
black victory spoke alloys
white indicators
darkened rear glass


extras all fitted in last year

quicksilver exhaust
koni active shocks all round
H&R lowering springs
EBC black discs and pads all round
Lohen chassis bracers
braided brakes line kit with DOT5
new rear arb bushes and drop links
all 3 engine mounts replaced
swapped out a number of items for black on the trim,

full set of unmarked silver loop alloys with non runflats
original victory alloys have winters with plenty tread

thanks for reading