I'm doing the PBJ-1H "8 Ball" from the Profi kit, and it's a great kit, but I don't think it'll apply at all for the J in any of it's variations except for one or two small details.
If I were doing a J, I'd source the radar pod from Lone Star Models if you're using the wingtip pod. For the ugly glass nose mounted version, you'll need to scratch it. Then just use masks for the decals. It should be an easy conversion.
There's lots of reference material out there on PBJs, including a couple of good books.
AMS props and gearboxes NEEDED, as are Brassin wheels and brass gear legs. Metal gun barrels are a must and of course, HGW seatbelts.
I think the kit pit is decent enough, although of course, I'm using the Profi H panel, gunsight and other goodies along with the right seat removed, etc.
Was mich nicht umbringt macht mich stärker
In progress: T-28C, T-28D from a C, MuG-23MF, Felixstowe F2a early, PBJ-1H, PZL P-11C
Completed: RCAF F-51D Mustang, ZM A-1H Skyraider, Tamiya A6M2, Felixstowe F2a early, Junkers J.l, Gotha G.lV, Pfalz D.Xll, Albatros D.V, Bf-109F4, Ta-152H-1