I've got a BRP with the Edelbrock quicksilver pumper, Ive got another XR with an FCR42 and I just installed a TM40 on a BRP for a customer. Of those three carbs the best performer by a small margin is the FCR42. The TM40 is a close second and the 'Brock is dead last and for good reason. The best value is by far the TM40. You can get a kit for the XR from Sudco for $480 and it will come jetted fairly close with cables and extrra jets. The FCR42 kit (also from Sudco)for the XR is $700 and in my opinion is a little better but not $200 better than the TM40. The Edelbrock kit for the XR is over $500 and I'll never buy another one as long as the TM and FCR are still available.
The 650R I just put the TM40 on was stock except for the exhaust and air filter does 3rd gear wheelies without even trying to now. By far the best value for a pumper carb.
Just a little FYI, disconnecting the accelerator pump when jetting this type of carb makes it much easier. After you've got the bike running perfectly reconnect the pump and adjust the shot timing and duration.
XR650R Plated Supermoto
XR628R Plated and highly modified
CR500R Still rips after all these beers
RZ350L Kenny Roberts Special
"If it's hard to do, you're probably doing it wrong."