o_O "compression chambers/boost"? If you mean 'Boost Bottles': Boost Bottle Industries
most say they're a waste of money, some say they smooth out the idle a bit, no-one saz you get any "boost" from them at all lol
If you mean "Expansion Chambers" ie, tuned exhaust - I use the Sick Bike Parts expansion chamber: Sick Bike Parts
and I'm extremely pleased with it's effect as are quite a number of other members.
If you mean a compression boosting 'Slant Head' for your engine: bicycle Motorized GAS ENGINE - 50cc slant head - eBay (item 150371910232 end time Nov-08-09 16:07:10 PST)
(I can't vouch for this seller/dunno) many here have them and report good things, but I haven't gotten around to this mod yet lol but apparently there's sometimes problems with piston/spark plug impacts, needing to space the head with another gasket etc.
Saddlebags? Gawd - I dunno what I'd do without 'em lol I commute with my bike and do grocery runs, heck - it's all I drive
My main transportation because I hate
the daily costs of a conventional vehicle (those schwinn bags are garbage tho, need better ones);