|There's a bunch of part numbers for a bunch of parts and those vary by who's selling them. You question is somewhat vague since you didn't supply any information on what it is you're looking for.
Typically, for most folks thinking about upgrading to a 2.2 liter, an owner would be interested in a 2.2 piston (these have a revised wrist pin location for the stroker crank) at 0.030" oversized . You'd get your machine shop to bore your old liners, and then you would need to consider what brand and what compression you want. JE is big name and certainly you can't go wrong there, but the guy that designed the well known JE piston has branched off and formed his own piston company, CP Pistons and those are at least the quality of the JEs. Prices are pretty much the same everywhere. The manufacturers don't cut you any direct deals unless you purchase a few dozen at a time. There are no parts sitting on the self for our application by these manufacturers, all the JH/Lotus stuff is custom done per order as the resellers (or racers) order them.
On the rods, many people use the stock ones after a recondition and balance, they are very durable. Something like a light weight Carrillo rod increases the cool factor and rpm, but figure an additional $900 for a set.