I am not really sure why that is such an issue about power for the new EvaGT, as it is as the name says a Grand Tourer and as Simon says, for me anything under 6.0 sec for 0-100kph is quick enough for this application.
:wave: I think the only one being concerned about power was me! Don't want to tar anyone with my brush! So back on my

I've removed those reservations based on the tunablity of the engine and the ample torque available from the twin turbo set up. SO I publicly promise not to bang on about power any more. After this post! :beer:
Based on information that we gleaned at the factory, it will be a full 4-seater (I'm sure that's in a GT context, if you follow my assumption) and not an additional 2-jump seats a la 911/Evora.
If they are able to hit the weight target of 1250 kg's, the same as a Series IV Aero for what must be a bigger car, then the bhp per tonne looks like this.
Model/weight(kgs)/BHP/ = bhp per tonne
EvaGT/1250/306 bhp = 245 bhp per tonne
I do really hope you are right, and I think if they can it will be amazing. Looking at the hole rather than the doughnut though the series 1 was supposed to be 1000kg - but was in reality more like 1150-1200.
The series 4 was supposed to be aroudn the same as the series 1, but tips the scales at 1350kg.
How Morgan can stretch the chassis to accomodate 2 more passengers, and put a coupe lid on the car, meet US crash regs, EU sound deadening regs and put in two more fully For reference the Lotus Evora tips the scales at 1350 (dry) and has a compact v6, as well as tiny rear chairs.
We have recently owned the following competing GT's and these are their power to weight stats:
GranTurismo/1880/400 bhp = 213 bhp per tonne
Porsche/1605/345 bhp = 215 bhp per tonne
Bristol/1650/380 bhp = 230 bhp per tonne
It would seem that the EvaGT is more than competitive using the power to weight criteria, though I feel that torque and how it delivers its power is actually more important in this application.
The GranTurismo actually felt somewhat underpowered as its peak power was developed at 7100 rpm and its peak torque at 4750 rpm, so you felt that you were always having to 'push it' to extract its performance. It was heavy too and thus you needed the S really which has 230 bhp per tonne, but still develops its power and torque at 7000 and 4750 rpm respectively.
The standard 911 develops a similar power to weight ratio and peak power and torque are at 6800 and 4250 rpm, but the PDK box makes the difference and the car feels lively at all times, basically because it always seems to be in the right gear.
Bristol do not quote power and torque figures, but it is generally accepted that the power is around 380 bhp, not unreasonable for a 6.9 litre mill. The torque is prodigious, as it needs to be as it is geared 40.76 mph per thousand revs in top.
I know which of the three cars I would rather drive down the Autoroute to the South of France in one day in.

I do agree and again I hope MMC can hit the target as the car will be a true engineering marvel. If for a moment though I suspend hope (looking at that hole in the doughnut again) then that 2 extra seats, plus extra chassis + extra crash protection, carpets and sound deadening, glass, upholstery, larger brakes are likely add only 200kg over the Series 4 Aero. Which gives us 1550kg which is a bit less than 20% over the estimated kerb weight - a similar margin of error as for the S1.
Doing the calcs for 1550kg the power to weight is 193bhp per tonne. Ok thats not a terrible figure, and for most it would feel more than adequate. For me though (indulge me) if I'm having to give up my Series IV, to have the EVA I would prefer to still have the option of at least a similar sensation of thrust! Besides if the car is giving up power on the pretext of being lightweight, and it's not really, then it would feel a bit of a letdown I think.
The Eva being a twin-turbo with 400 nm of torque (300 ft lbs at 1300 to 5000 rpm) and a pretty light car, this is key to the mix, I don't see why it can't be competitive out-of-the box, and there is little doubt that by the time it is launched BMW will have extracted more bhp/torque out of this engine.
If you want ultimate Morgan performance get an Aero Series IV (or tune an Aero or a Roadster), but let's keep the Eva as a true GT as it is not conceived as a pure sportscar or a Series IV replacement.
I do completely see where you're coming from, and of course as a prospective purchaser I do hope that the quoted weight is realistic.
Equally as I've pointed out, with the engine tunable to a comfortable 374bhp, with would provide a very healthy 240bhp per tonne (Even at 1550kg) - which may not be anywhere the ultimate performance of a Series II with the wick turned up (Boshers!) but certainly enough to feel that you haven't missed out too badly if trading on from a Series IV (aprpox 260bhp/tonne).
Even better if the eVA really does come in at 1250kg, with 375bhp it's running 299bhp per tonne, which should be ample to keep and accompanying canine with it's face pressed to the rear screen
I'm still sold - lets hope we get to see more teaser pics soon, can't wait to see what it looks like - surely it's sitting in a well protected shed in Malvern right now looking amazing.