The 32/36 would be your cheapest power upgrade out of all of them on a stock engine....

but don't pay more than $50 for a 32/36 at a wrecker,
buy a rebuild kit $30,
Air filter the redline box filter with assembaly is about $25
Adaptor plate $35
put it on yourself, it's simple, use the throttle linkage from your hitachi and the throttle cable goes straight on.
go to the weber site and get these diagrams and tuning pages
http://www.redlineweber.com/html/Tech ... _dgev_parts_breakdown.htm
http://www.redlineweber.com/html/Tech ... set_up_and_lean_best_.htm

you will be sorted very cheap upgrade.