Steve, id stick with the standard ones myself if i were you. You have virtually no lag with them as it is and i think if Rouse could have put different ones in without compromising the driveability they would have done.

You want to come and have a shot of my Escort. Then you will see lag

Just get the head off of it give it a nice freshen up with some new gaskets / seals ect fit a GP-A head gasket & your new turbo and go and enjoy the thing

Remember im only over the hill if you need a hand Just give me a shout.