Should be a lot of fun, but perhaps not for too long. 2 tonnes on Astra suspension and skinny tyres . The transmission may be OK as a lot of it was borrowed from the 2MT70 transaxle that itself was derived from an Allison design for buses. But it will surely be a toss-up as to whether the inverter cooks in hooligan mode before the manual disconnect fuse blows. Let's hope he did more than just patch the code.
1.56 tonnes. And (front) suspension is beefier than Astra's (just beam axle in the rear). So biggest issue is whether battery can survive extra load. Torque decreases at speed anyway, so trasaxle and CV's should cope fine as long as you do not do drag racing.