AdService.ts

@Directive({
  selector: '[universalAd],[universal-ad]'
})
class UniversalAd {
  constructor(
    @Attribute('id') public id: string,
    public adRegistry: MyAdRegistry,
    public elementRef: ElementRef,
    public cdRef: ChangeDetectorRef) {

    if (this.adRegistry.isRegistered(id)) {
      this.adRegistry.reattach(id, this.elementRef.nativeElement);
    } else {
      this.adRegistry.registerElement(id, this.elementRef.nativeElement);
    }
    cdRef.detach();

  }
  ngOnDestory() {
    this.adRegistry.detach(this.id, this.elementRef.nativeElement);
  }
}


@Component({
  template: `
  <div universalAd id="importantAd"></div>
`
})
class App {
  constructor() {

  }
}

@NgModule({
  bootstrap: [App],
  declarations: [ App, UniversalAd ],
  imports: [
    UniversalModule
  ],
  providers: [
    {
      provide: MyAdRegistry,
      useFactory: () => {
        var listOfAdIds = {
          'importantAd': document.getElementById('importantAd')
        }
        var listOfClientElements = {}
        return {
          isRegistered: (id) => Boolean(listOfClientElements[id]),
          registerElement: (id, el) => listOfClientElements[id] = el,
          complete() { 
            Object.keys(listOfClientElements).forEach(id => {
              // todo: use raf
              var ngEl = listOfAdIds[id];
              var serverEl = listOfClientElements[id];
              document.removeChild(serverEl); 
              ngEl.appendChild(serverEl)
            });
          },
          detach(id, el) {
            var serverEl = listOfClientElements[id];
            el.removeChild(serverEl)
          },
          reattach(id, el) {
            var serverEl = listOfClientElements[id];
            el.appendChild(serverEl)
          }
        };
      }
    }
  ]
})
class MainModule {
}


platformUniversalDynamic()
.bootstrap(MainModule)
.then(moduleRef => {
  const adRegistry = moduleRef.injector.get(MyAdRegistry)
  adRegistry.complete();
  preboot.complete();
  return moduleRef;
})

I adapted this to a general passthrough directive. Still needs work but I have this concept working here --> https://github.com/pxwise/universal-passthrough