Never heard of it. I'm very suprised that you've had multiple people recommend it, are you sure they're not in collusion? :)
If the ASP2DLL is the same product that gets returned when you search for ASP2dll on google, then I'd personally avoid it like the plague, the advertising reeks of FUD to me.
VBScript code is easily ported to VB (without 3rd party tools). If you want to speed things up a bit do that. Ideally you'd choose C++ rather than VB if you're looking for performance gains on existing code.
More than likely you'd be better off simply optimising your existing code, caching is usually a good solution for quickly easing bottleneks if the code doesn't implement it already.
I was already planning on optimising the site for speed via caching and other such technologies. I realise COM is an options but I need quick change and development time as the site needs to be adapted on amost a daily basis. Finally, about ASP2DLL. I'm avioding it.