hi been looking on ebay and there are some tre's for sale has anyone used them and do they help with low speed town riding my bike coughs back fires and sometimes stalls around town ?
Ivan's thing will do nothing in the 1st 4 gears and nothing in the upper gears below 7600 rpm or so. This is where the stock restrictor kicks in by manipulating the secondary's to restrict airflow.
By removing the secondary's altogether there is no need for a TRE and you get better airflow throughout the RPM range.
"coughs back fires and sometimes stalls around town"
Do a TBS synchronization, however as you start to put the miles on your bike the throttle body's will ware at different rates making it harder to sync them throughout the rpm range. Fear not there is a fix.