No because the injectors are still bolted to the new motor, and the wiring harness you need is already connected to them. Disconnect the bulkhead connectors. Heave the old engine out, and ho the new one in. Plug up the new connectors to the old chassis harness. What' you'll need is the ECU from the other car because the fuel maps are different in those ECU's. Not familiar with the UK models, but in the US, that's all you'd have to do.

Cvchtchbk92: If someone can't beat a viper on a $10k budget, then they started with the wrong car. A USED Viper is $50k.