Hi Bryan,
Rare Spares and Spectrum are generally the same nowadays. Some rubbers are different (inner door rubbers) but Spectrum are just selling Rares stuff. The rest I'm not sure of but others will have experience.
From what I have seen there are NO rubber kits that fit, just one's that can be made to fit
I put Rares Rubbers in my car and it doesn't leak, the doors shut OK, the boot shuts with minor persuasion, and they look good. The 1/4 window upright rubber is the worst of the lot, it's not even close to the original, but again with some fiddling its "OK".
This topic has been discussed many many times on the forum so do a search, read up, and you'll end up with something that'll do the job.
A word of advice though, take your time and make sure get someone to help you, preferably someone who has done the job recently. Another reason to join a club.
Good Luck,
Craig.