Let's not forget, the Spa circuit has seen some lay-out changes (namely around Bus Stop chicane and La Source hairpin), as well as a re-surface in recent years. We have no idea what condition those lap times were set and thus hard to confirm/disconfirm them.
SR8LM is very close to an LMP2 in term of raw speed, here is one did 2:17, if you time it at the start/finish line before the hairpin.
The 2:25 does seems unreal, there is a guy did 2:29 in championship.
With a different layout, different weather condition, and different driver... who knows?
By the way, SR3 RS DOES come with slicks, check radical's gallery.