uf10/11 front end to uf21

Has anybody seen how to do this conversion? Someone hit my gs300 a couple of weeks ago and I got my replacement yesterday. A 91 ls400 that has light front end damage. Since I'm gonna replace the whole front end, I thought it might be a good idea to upgrade. I know how to do bodywork and sheetmetal work but I just wanna get a light idea of how to do it and if it can be done with all stock parts instead of using a kit from japan with fiberglass parts.