I had a raised one on my small block. Back-to-back with a Victor Jr the G outperformed it. I have a raised Team G on my BBC and like it. The raised one makes more power than the low one Car Craft tested if you can fit it.
Very little power can be found in the roller tips though. The power can be found in a roller fulcrum. The roller tips do reduce wear on the valves however...and you are correct, the Comp pieces are way more accurate.
I wouldn't spray it at 2500rpm with a window switch. That's a bunch of load on pistons. Just an opinion...
Sounds like it would be a killer combo w/100 shot. Those pesky Stangs will melt to glue.
I know I installed a set of IK200s on my brothers 3rd gen several years ago. They have done very well. Of course, these are all opinions, but I only go by personal experience. And mine has been great.
Regarding the tall valve covers and power brakes, I still use these and run a solid cam, so I remove the valve covers to run the lash and did notice that the tin covers I use "clearanced" themselves but putting a small dimple on them by the booster...
And I use stock springs w/iron heads and...
He asked about a "different intake, such as an air gap". The air gap is different than what he has now. A single plane intake would certainly qualify as different than the current Performer...
Be prepared for 14 posts after I say this asking me "Are you nutts?! This is a street engine!! Single planes don't work on the street dummy!!" I'm going to say this...go RPM Air or a single plane. I don't know your cam specs, but I would imagine you have some duration if you have a roller...