Seat belt advice

[Repo Man]

Hi there. I've a pair of Recaro Speed seats on the way for my '67 Camaro. My car only has the original lapbelts. While I might have a cage someday, I won't anytime soon. I've thought about just replacing the lapbelts with some Simpson ones, but I was wondering if anyone might have a better recommendation?

Also, for anyone reading this who has retrofit Recaros into their first gen, how hard are they to install?