I have a SX4 90 HP with VGT. Yes SX4 DDiS has also lag section between idle RPM to 1300 RPM. But I am talking about drivability in lag section. Both DDiS I mean 75 & 90 HP has no heavyness & poor throttle response even in lag section also. Turbolag & bad throttle response these 2 concept are different. I use same bunk for my DDiS 90 & MJD 90. Still I get bad performance from my MJD in lag section. & better throttle response from my DDiS in lag section. That's why I mentioned that it is my experience that DDiS,Quadrajet,TDi,CRDi are more suitable for bad fuel.