Well I can only comment on the MK1's so here goes.
You get basically the same interior as the HLX, the dials are just 4, speedo, revs, fuel guage and water temp.
On the roof are the controls for the leccy suroof and courtesy lights. Also the ultrasonics for the alarm are built into the roof unit.
As for seats, I cannot remember what the normal HGT seats are like as I have the leather, which is very nice, only came in one colour which is grey. The whole of the seat is covered in Leather, not just the centre.
The door pods front and rear are also covered in Leather, and are ruched and not completely smooth, looks very nice indeed, even if I say so myself.
The steering wheel is nothing special, covered in leather but I wouldn't call it sporty.
The gear knob and gaitor are also leather. Again in a non leather interior I don't know about the gaitor, I would assume it would be.
The controls for the heater are standard Bravo I guess, if you havbe air-con in a MK1 it's just an on off button, also the control for interior or exterior ventilation is a button on the HGT and not a slider.
You get front fogs on the HGT as you do on the HLX I believe.
It's pretty understated to be honest, definitely not an in your face multi-coloured lax power hot hatch.
I like it, it's a very solid feeling interior, albeit a tad plasticky.