:dude Sweet! I look forward to more of your reviews and good luck with the collection!
I have 10 Boss pedals these days. I like buying them used and under $50.
My Boss collection.... all MIJ (cool factor:)) except the models that are only MIT made.
These days the kits can be more expensive than a new/used, MIC knockoff/clones. The DIY typically comes with better quality components of course. I built two of the BOYC kits (two knob bender and phase 90) and they came out sounding pretty cool.
Fuzz Central is a pretty cool site for old dirt...
That champ amp has a few modulation FX built in (iirc). I would go with a wah and a fuzz at least. I like the 535Q wah that Dunlop makes. It's versatile. Dunlop also makes all those mini fuzz pedals which are cool. Those two pedals and maybe a tube screamer if the amps OD don't do it for you.