Never removed engine or subframe for the sump. If you're looking at that and have no idea on the ECU, I have worries you'll end up spending time learning and the labour cost will be higher than usual.
Changing the exhaust manifold for a turbo one and installing different intercooler pipe work is fairly straight forward.
Personally, I would just get Whifbitz to fit the kit. The installation, may be cheaper as there is less for them to learn. Unless it's a friend helping for an extremely low cost of course.
ECU's come with either an adaptor loom or needing wiring in. Emanage piggy back ECU is a typical NA-t ECU used. I have one for sale in the for sale section.
Whifbitz could supply, fit and map the setup for you. AEM v1 and v2 EMS is a commonly used standalone ECU.
There are lots of guides on what is needed. Just continue your research.
Whifbitz fit my own pieced together kit 7 years ago. We all know someone who could have a go. But Whifbitz have fit so many kits, it just makes sense.