Hi I don't have the T3 but I have the stock V40 T4 CC manual which is essentially a T3 with a different engine map. I took delivery of my car in December and have covered 3000km already. I recently started using fuelly to track the consumption.
http://www.fuelly.com/driver/bodg3r/v40
I found the V40 to be pretty fast but the car only really takes off after 4000RPM. I drove a Seat Ibiza Cupra TDI (118kw 330nm 0-100km/h in 7.6s) before the Volvo and I do miss the Diesel a lot in terms of the kick in the back it used to give from 2000RPM. I only test drove a T4 and a D4 both have plenty of oomph but the D4 doesn't come in a manual so that was ruled out.
I commute 104km per day and the power (132kw) from the 1.6T is perfect, allowing me to accelerate past Toyota Yarises and polo vivos that clog up the fast lane on my way into Cape Town. On the weekends its great fun around some of the coastal roads here, it responds well when you keep the revs up which is quite a mind shift from driving a TDI and the power is smooth all the way up to 5200RPM when I prefer to change.
I think I may get the polestar upgrade to increase the torque to 285nm I hope it will make the V40 feel more like the 330nm I was used to in the TDI and may even save more fuel in 6th gear on the long open sections of the highway. The only thing holding me back is the cost, at R10800 it is a lot and considering the modest power gain the only real thing to look forward to is 45nm of extra torque.
Sorry I couldn't give you a comparison between the T3 stock and T3 polestar but I believe that the polestar upgrade will be very beneficial to the T3, much more then on my T4.
Regards
Graeme