More than happy to post some thoughts once I've done a few km's in the Calais V. I've only just brought it home at this stage and only done 15 km's in it and yes I did about 1500 km's in the LT.
Just posting this as I wrap up my time with the LT.
Had the LT for just on 6 weeks and to be honest I'm a little sad to see it go. Such a smooth giving motor with plenty of low, mid range and top end power and a really wide spread of torque. Engine has no apparent vices and spins up freely to the redline with no noticeable engine vibration at all. Lovely light and nimble car with sweet neutral handling and pretty good brakes for standard Holden fare...really enjoyed my time in a nice light 1500kg car coming out of my 2100 kg Chrysler SRT8 which I owned before coming over to Holden again. That said there 2.0 liter cars they go best with one person in them and as soon as you start adding passengers the extra weight makes itself obvious and dulls the experience somewhat.
Honestly if you're not into all the latest technology and equipment, (I am a bit) then the LT or RS do the core business of driving in terms of power, handling and braking very well indeed in my opinion so save yourself a ton of coin and get one of the cheaper model's. You won't be disappointed.
On the other hand if you're into having a decent stereo, heads-up display, LED matrix lights, heated cooled and massaging seats, sunroof, adaptive cruise control, 4 wheel drive, torque vectoring and so on then the decision is much harder because while all this kit is really nice to have, arguably it adds little to the core driving experience but adds a fair bit of weight and a lot of cost.
Initial thoughts are you can definitely immediately notice the extra 200 kg's of weight jumping out of the ~ 1500 kg LT into the V6 ~ 1700 kg V6 Calais.
Happy to post some more thoughts once I've got better acquainted with the Calais V again.