Airwaves states this photo etched airbrake and spoiler set in 1/48th scale is for the Monogram F-84F, and "may also fit Heller." The interpretations of the airbrakes on the two kits are substantially different, so it is highly doubtful this set would work with the Heller Thunderstreak.
This detail set is photo etched from brass, and includes parts for both inside and outside surfaces of the speed brakes and spoilers. As with any good photo etched parts, these are clean and well detailed. My only "gripe" about the set is that the instructions are quite cryptic, especially as concerns the manner of cutting out the spoilers from the kit parts and inserting the photo etched parts. Even so, the parts are a considerable improvement over the kit parts if super detailing is your forte, and you are good at reading between the illustrations.
Airwaves brass photo etched speed brakes and spoilers for Monogram F-84F.
This Airwaves speed brake and spoiler set is slightly high in price for what you get, but the quality is there. If you want the significantly improved details this set provides, it's the only game in town, albeit a good one.