As Gonzo says, the RRP of the G25 is £280, and it's available for ~£120, so I'd take sod all notice of that for now.
I'll be sticking to the G25 too (though with BRD Speed 7 pedals).
The only competition Logitech have in the medium-quality racing controls department is from
Fanatec. If you're looking at a G27, then you really should be getting that instead - it's a much better wheel. G25 still holds the value-for-money crown in this market segment.
The G27 is just an option, with a few tweaks here and there. It's not for those who have a G25, it's for those who are looking for a wheel.
For the record, it's missing the sequential shifter that the G25 had. The G25 let you choose between H-pattern and sequential on the shifter (or the paddles).
aidanjt
Not in recent years.
iRacing is the best sim ever released, and by some distance. Though if your concern is financial, then it's not for you.
rFactor has plenty of mods, though how close many of them are to reality (the fantastic Cart Factor excluded) is very debatable.
NASCAR Racing 2003 is still up there with the best, and GPL is still as immersive as they come, though looking a bit dated now.