bro any recommended shop good with java bikes? fine tuning and acc for me to waste my money ? 

11-40t or use smaller chainrings.
Actually it's not that simple. Your leg power is the main factor.

11-32t + 53-39t is good enough

if im not mistaken,
ira supposely used 11-28 casette with 52/42 chainring. as for 451, 42t is heavy pair with 11-25, unless ur leng is strong.

for me best setup for ira is 52/39 with 11-28 casette. my friend ira already change his chainring to 39t for better climb, without changing his casette or add extra link on his chain

anyway, 11-28 is a close ratio road casette and 11-32 is mtb casette. u will feel small jump on close ratio casette in flat condition. where else the mtb casette do give u a big jump on flat but easy for climbing.

oh ya, if u change 11-32 do remember to calculate back ur chain.maybe u need to extend ur chain to accomodate those 32t on ur casette. no problem with rd since sora from ira already medium cage.

Allow me to suggest changing the cassette instead of a double chainring. Much cheaper and easier to swap. Since the original is an 8-speed, I'd suggest looking for an 8-speed wide ratio big sprocket. Something like 11-42t. That would give you the lower gears for easier climb without having to change cranks and add derailleur. Much less hassle. Only the rd cage might or might not be changed but rd cage is cheap enough if it needs to be changed anyway.

in some cases, u need to change the chain coz hassle free. but if ur lbs are kind and good enough, they will extend your chain and make it longer.

try to scout 8s casette with mega range ratio.if im not mistaken the biggest cog for 8s casette is 34t is available. do remember also ur rd be either medium or long cage to accomodate that casette (in some cases rd can be tune up)

a work in progress, not mine actually..

I have similar bike like yours.. with same tyre size, changed to Schwable kojak (brompton size 16" x 1-1/4") and it direct fit no issue ..

You might use the 305 tubes but not the 305 tire. 305 tubes can be stretch out to be fitted in your pikes. The 16" used on pikes/brompton is not really 16". Its actually close to 18". 17  3/8" iinm. So the difference is about 2 inch.

As for varieties for 349 tires, schwalbe offers several model. Marathon racer, marathon plus, kojak and one.price start from rm200 to rm500 per pair.