Okay, pretend I'm your best friend and you trust me enough that even if I say something harshly to you that I mean you no harm or disrespect.

So you're willing to pump "big bucks" into the inside of your engine, but want to go cheapo on some parts that will make your engine look bad (dripping black greasy crusty crud), cause smoke under your hood (bonnet), and drive you crazy? What's wrong with this picture??

Personally I've not enjoyed (?) your bad experience with with center bolt covers. The real likely problem is the same as with side bolts. Cheap, piece of crap, cheap, flimsy, cheap, poor quality, and cheap covers................especially the $29.95 (US) chrome jobs. After that it's hiring a gorilla to tighten the fasteners.

The stock GM covers are of a good gauge steel, and have those ribs in the top to add rigidity. As for cost alternatives, you can often buy Corvette magnesium take offs for under $100 (US). If you're married to the idea of side bolts you can get adapters that will fit side bolt covers to the center bolt heads for around $120. Whatever you do, don't over torque the fasteners, and think about spending a few bucks extra (compared to the cheapo junk pieces) and don't make a problem for yourself.