Having had a tweeked XR2i 8v until very recently I can say it sounds like you have problems.

I beleive the rev limiter should cut in at about 6200rpm and you should pull just shy of 60mph in 2nd gear. If you are in doubt about tackling this sort of thing you may be better off booking it in with a specialist to sort as they will have the equipment to diagnose your problem(s). What area are you in as PassionFord has people all over the country so wherever you are somebody on here is bound to be able to recomend you a company that will help you and not rip you off.