Honestly pal, your dealer was talking rubbish. The components really are exactly the same across all chassis types, unless you choose 180, 184 or
cupra in ALL bodystyles which all get the multi link rear suspension setup. You are far more likely to notice a front/rear balance difference by switching petrol or diesel. The difference weight wise is larger between engines than it is between chassis.
1.4TSI FR 5dr ( without multilink) 1231kg
1.4TSI FR ST 1276kg.
2.0TDI 150 FR 5dr ( still without multilink) 1305kg
2.0TDI 150 FR ST 1350kg
Step up to a 184 though to get the multilink, and that's where the weight comes from... On all chassis shapes. You're adding about 40-50kg just in the extra components.
2.0TDI 184 FR 5dr 1345kg
2.0TDI 184 FR ST 1415kg
If what you want is to not feel the difference then ironically you want the
lower spec model... Stick a pushchair in the back of a five door and your weight balance would match an ST almost exactly!
He was more likely to be comparing a 150 ST with the 184 5dr, in which case there is a difference. But you'd have noticed the same thing in a 5dr without multilink.
You can rest assured that a
Cupra ST is absolutely guaranteed to have the multilink setup... And feel every bit as good to drive as a 5dr.