Team-BHP - ZEN 99 - Looks & minor performance upgrade

:) Hi BHPians,Kindly Advice,

I am planning to do minor modifications to my 99 DEC model Carb Zen(47000km).As Selling it is not fetching value and buying a new small car isnt pleasing me much.

PAINT JOB:
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Firstly i would like to change its looks(paint job),currently its colour is PRed(mettalic red not the bright one.)

I want to have a good quality paint job, something like which starts silver in the front and merges to mettalic black towards the B pillar.and the black may have green 010101 vertically like in the matrix screen saver(just an idea).

Kindly advice about the paint that would look good in my zen.
HOW MUCH? i dont want to spend more than 30k on it...!
ALLOYS :
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Tyres are new but stock 145/70 R13 will change them later, but planning to have chrome alloys.
HOW MUCH? i think i can get it for 15K
K&N & Free flow:
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I dont want to Compromise on milege, bcos alrdy i get only 10.5 with AC in city.a little increase in pck up will do for now.
K&N air filter which model? how much?
Free flow exaust: How much?(do we need to change from headers)
(will these two be done for 10000)
Esteem engine(sometime Later)
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Esteem carb engine is 65 bhp, this is the similar capacity that comes in wagon r and santro and many small cars.will it make
a good diffrence in zens engine bay.i have driven wagon r but i love my 50bhp zen engine(although 50 bhp with ac struggles).
How much ? what is the mil that i may get after i put esteem engine in zen?
i have alrdy fitted it with a pioneer Dolphin display(dont remember the model) head unit, JBl 1000wats sub, sony 4 channel
amp(costs 28000). will send snaps soon.
Waiting for all your advices.

Thanks.

PAINT JOB: a good quality paint job 1ill not cost u more then 20k. i got my zen repainted white colour for 10k which also includes some small dents removed black colour will suit nicely for zen ..but it has some draw backs its a headach to maintain black and it may also get faded after some days if the paint quality is not nice..

WHEEL AND ALLOYES: 13 inch alloyes will cost u 12k and go for 155/60/r13 thats a good upsize for zen any thing more then that will foul with the body

K & N FILTER: go for universal filter that may cost u 7000/-