Hi guys might sound like a silly question but do all three models have the same engine size? and is one more reliable than the other

or all pretty much the same? thanks

All the same I think.

Yes, they are all 998cc (1L) 3 cylinder. 

ok thanks

140 model has different gear ratios, apart from that i believe all engines are same apart from mapping

I have read on another forum that 100HP and 125HP should be the same, but with difference in mapping.
Turbo and manifold should be different at 140hp.

Sendt fra min SM-G975F med Tapatalk

If you look at superchips bluefin figures you will notice that all three have the same standard torque figure.

Also bluefin improves ALL three to the same torque AND BHP figure, therefore, don't waste your money on a 125 or 140 just buy a 100 (which is also cheaper to insure) and bluefin it

2 hours ago, DaveT70 said:

Also bluefin improves ALL three to the same torque AND BHP figure

The Bluefin site shows: 154, 157 and 158 ps respectively for the 3 versions, so they all end up basically the same.

I suppose it would be a question of balancing the loss of warranty and possible higher insurance on a modded car, plus the Bluefin at £399,  against the saving on initial purchase (100-125 £500, 125-140 £320).

As far as the unmodded cars go, I've found the 140 nippier than I would have expected for a 15 PS difference compared to the 125, probably due to the lower overall gearing.

 

140 has lower compression through a thicker head gasket to achieve higher boost, different turbo (125 had same until 2016?), and a different final drive ratio also. Arguably the 140 is a better engine to tune as some of its OEM components are built for higher levels. 

All are good for what they are, small fun cars. They are not fast cars. If you want fast ( an extra 3 or 4 seconds of faster accelleration) get your hand much deeper into your pocket for the 200bhp ST.  

OP hasn't visited for over 3 years - probably bought one by now!😀