If that Enlight power supply is a legit Enlight unit, you're probably better off leaving it alone. Enlight usually built some pretty good PSUs back in the day.
Spire on the other hand... well, as far as I recall, they didn't build *any* PSUs. They just slapped their label on various OEM and non-OEM vendors' units. While the quality of their CPU coolers was pretty good, their PSUs varied between OK/good and kinda-lame. IIRC, I saw at least one Spire PSU with Solytech/Deer/Allied internals (which is a so-so PSU manufacturer, though they do use cheapo quality electrolytic capacitors.)