Thanks for the responses. CYMA seems like a good option what first few upgrade would be best.
Jeeeeeeez
if you look, Luke kept nigh on most things stock
you don't need a bearing spring guide coz it comes with one
he kept the stock brass barrel, stock nozzle etc....
afaik it was kept nigh on stock mechanically wise, just a clean & regrease etc...
then fitted a mosfet - but even then not a must have out of box
a clean up, maybe new piston o-ring to boost a 330fps gun to nigh on 350
and that seems to be it - but he is very very experienced
so as said, use it for a while and only bother to upgrade & replace stuff as & when needed
£150 gun leaves £50...
£28 motor RA HT for 7.4v but can use stock motor on higher juice
(can't really go nutz past 20rps on full stroke AK imho)
So motor upgrade is really an as & when upgrade
I personally would grab the metal rack piston for a fiver, maybe nozzle
but not rush ripping her open if you are not clued up & fuck it up
Mosfet - well a basic £10~£15 will suffice or something
The barrel is not that bad, cyma barrels are not crap and crowned well I reckon
Maple bucking & nub at some point perhaps but barrel change only if cyma one is really bad
THAT is about it - you don't need to go nutz & even if/when you don't need to upgrade everything
it seems to be a pretty decent gun as is...
Which is what you asked about & what you get over a 028 or cheapo 520
well that 077 cyma looks to be very good bang for your buck
even though the gearbox/motor looks exact same as 028
you get metal lower receiver and a pretty nice looking AK for not a lot over the 028 price
(they just bothered to paint box black - that is all)
the bearing spring guide is good to know
use it as is, clean barrel, get your head around hop setting & just go with it
everything is detailed in vid, well briefly detailed, but it shows a decent AK doesn't have to cost the earth
even the 028a 2-toned from say patrolbase ain't bad - really it ain't for a first gun
https://www.patrolbase.co.uk/cyma-cm-028-tactical-ak47
or somewhere decent
(don't get the 520, has more plastic bits than 028a & by the time you replace them best bought the 028a)
then if you wish get the 077 if you still want when ukara'd blah x 3
(flog the 028 if you wish or keep as a spare)
but don't think you gotta upgrade stuff asap
and if you are new to this - maybe consider getting somebody like Luke to tweak it
get your feet wet maybe but don't try to run before you learned to walk regarding upgrades etc