I wonder the durability of such a procedure and if any bore flex occurs?

The TS Cup cars in Japan get around 175hp out of A13's.
I know of a a15 race car in NZ with 200hp.
These would be at the flywheel. The race car here is very competitive and beats vtec civics all the time in ss2000.

If you look at ferals a13 with titanium rods and other bits this is understandable
but 80mm bores are hard to swallow for durability

I got my A15 with std but lightenedand balanced bottom end,cam,head job and daul webers to 115hp at 7200rpm on the fly wheel, how much will it be in wheelhp?

To estimate flywheel net HP form RWHP, remove 20%. Some say up to 35%.

I would estimate your 115 rear-wheel HP as 95 net HP. Very very good for an A15. Rear-wheel dynos are notoriously inaccurate, so take it all with a grain of salt.

My A15 with 11.75:1, standard valves,ported head, rally cam got 91hp at the wheels after quite a few events, was starting to smoke on the dyno so probably needed a rebuild. This was an old rolling road type dyno, running on rally tyres.
Some good numbers being thrown around here but unless you've got the cars on the same dyno, same day, same everything comparisons are a bit meaningless I reckon.