I feel I'm going to regret saying this .....
Why would you want to put UK spec turbos on your car and it take a little longer for them to spool when you have been used to the j-spec ones ?
Would you not feel that this was a step backwards ?
Well, maybe not backwards but, If you fit them and you go out and have a blast you might not be happy with the different characteristics of them.
I have not driven a J-spec so, can't comment on the spool up difference from personal experience so, am happy with my UK's till they blow but, given the choice and from what I read on here, I'm not sure if the UK's are the right step for you m8.
Since funds for anyone at this time of year is not good, then maybe a second hand set of j-spec turbos are for you ?
However, all the above could be crap and is just IMO but, hope it helps chap.