I have the Billm Cool Mod and the Twin Stack Mod on mine and love it. I also swapped out the sorry arsed stock speaker with a Celestion Vintage 30 clone. I tried a Jensen C12N in it and it really brightened up the amp with the mods but it was a little too bright for me and I wanted that Celestion ooomph with Humbuckers and pedals so I put in the V 30 clone and have been happy since. I highly recommend you mod your stock Blues Jr. you will be pleasantly surprised at how good it will sound after.
Guitars/Bass - MIM Fender Classic 50s Strat, MIM Fender Standard Strat, Squier Classic Vibe 50s Tele, Gibson Les Paul Studio, Epi '56 Gold Top Les Paul, Martin DSR acoustic, Sigma Martin Auditorium electric/acoustic, Squier Jazz Bass.
Amps/Cabinets/Modelers - Model 2558 50 watt Marshall Silver Anniversary Jubilee combo w/ Celestion Vintage 30s, 4x12 Marshall cabinet w/25 watt Greenback Celestions, Fender Blues Junior w/ a couple of Billm mods, Line 6 POD 2.0, Roland Micro Cube
Pedals/Effects - Cry Baby Classic Wah, Boss TU-2, Boss NS-2, Boss RC-2 Loop Station, Ross Compressor, MXR Micro Amp, Danelectro FAB Echo, Danelectro FAB Chorus, Danelectro Chicken Salad, Marshall Guv'nor Plus, Marshall Echohead, Duhvoodooman's Zonkin' Yellow Screamer, Digitech Digiverb, Digitech Bad Monkey, Dunlop Fuzz Face, Homemade Loop Bypass pedal, Duhvoodooman's Sonic Tonic (Maxon SD-9 clone +), Voodoo Labs Superfuzz