mine are welded onto the top of the tubes.the AIR connection is in the same place though.

 

i got the TES for my Monte SS. Well worth the extra money

 

Buddy of mine had the edelbrock headers and y-pipe from edelbrock with air tubes and they seemed great. My advice is if you do end up getting the custom y-pipe made, get long tube headers like the hooker super comps. I had Hooker Comp shorties and then made a custom y-pipe which ended up being a pain because the tight turns to get across the oil pan etc. required mandrel bends for enough clearance. Also, if you do the custom pipe, I would highly recommend getting it ceramic coated to preserve it. I had minecoated for 100 bucks. I'm kinda in the middle on getting the headers coated. I've had sets on other cars coated and the coating within a few years flakes off. It just delays the rust a few years. I understand if you're on a budget the long tubes and custom pipe are not the way to go since they're expensive, but it is the best way to go. But for emissions, everyone I know that used the edelbrock headers and y-pipe with air tubes had great luck with them. I would check ebay too. Once in awhile you'll see some nice headers go off for good deals. I got my HookerComp Headers with ceramic coating from JETHOT brand new for around$275.