Interesting observations, and all valid points. The VAG 1.8T is proving more popular due to wider prevalence of available units, and better future availability of parts. Honda VTECs have begun to change to new architectures, I think, so parts for earlier ex-write-off engines will become harder to source. Yet there are soooo many VAG 1.8T units going around, and still being fitted in new cars today.
However on the weight thing, do also think of the following contexts...
I guess the lightest driver weighs around 60kg. I am probably around 70, and still pretty average. I know many Elise owners who weigh a good deal more than me, so let's say they get as far as 90-100kg. At which point you have already created an extra 30kg weight purely in the driver ;-) The Elise will have been designed for this variation from the outset, as are all cars.
Next up, consider the use of the boot (yes, it does have one!). Fully packed you could easily have 20kg in there. And yes most of us will travel with empty or near-empty boot, many of the guys I know take their Elises on European trips with plenty tools and backups in the boot so a few kg will always be sloshing around Again, the car has this tolerance designed in.
Finally, variation in fuel tank load will also range from practically 0kg to maybe 25kg (think petrol is lighter than water so the 37 litre tank will only ever weigh maybe 25-30 when full). Again, this has to be built into the design parameters of the original car.
My understanding is that the Honda conversion amounts to approx 30-40kg increase in engine/gearbox weight also, and the general consensus is there is no material affect on the handling of the car. And naturally, power to weight improves markedly despite the extra mass. One key point to note is, the Honda tuners have all come round to the importance of a minor change to the rear spring rates, which I think they take up by a few pounds to prevent the car "bogging down" when moving away from standstill. Feedback from a couple of guys I know who've applied this is very positive, and they say it dials out any weight effects they ever noticed.
And whilst the weight increases are indeed behind the central axis of the car, they are still within the axles - it's mid-engined after all.
I see you have a neat wee Se7en in your signature...so I realise you do know your stuff when it comes to lightweight cars, but bear in mind the Se7en is TRULY lightweight and 40kg there is a huge proportion! Practical feedback says 40kg in the Elise world is not a crisis...and since the earliest S1 weighed 720kg and the latest nearly 750kg (if you fit the hardtop etc), this just becomes lost in the noise.
Campbell
PS - I don't have a converted Elise, and mine is a "mid-life" S1 with no significant mods, so I have no axe to grind...just enjoying watching the engine conversion debate in case my K series blows up one day and I need/fancy something a bit different ;-)
