a whole load of issues

[xxxscimitarxxx]

to save posting a lot of threads here are all my probs in one basket

1.
at about 100mph i noticed that the acryclic top started to part company with the frame top at the front...BRAKES!..quite a shock to see it lift but it didnt rip or crack so what the fix.....glue l assume....any recommendations for what to use

2.
looked under my 92 and saw that the rear cross frame rail connecting the two chassis rails behind the axle had corroded quite dramatically.....it was holed through in places.....and the unit seems to be double skinned.....l havent found a replacement part for this but assume there is one l can weld in...whats the part called or can l just weld in a box section to replace it

3.
my 90 starts fine....runs at 1000rpm tickover for a while.....then goes to 1300 ish when warmed up and stays there.....if l stop for a few mins and start again it runs at 1000 .....then after a short while goes to 1300 again....lm assuming this is somekind of vac leak.....time for plenum service?

4.
90 again....why does the service ride control warning come on....occasionally!

l can start sometimes and its on...or other times not....then on it comes....then stop and start again and its gone.....drives me nuts thinking have l got a ride control prob or not?

5.
my 92.....secondary vac pump.....on all the time.....guessing another plenum vac leak...but seems to pull hard anyway...no SEL..(guessing thats two plenums to service )

6.
92 head lamp beam/dip switcher only works if my steering column is fully down...but cant drive that way......is this a common prob

cant think of any more gripes for now.....LOL.....but hey its a ZR1......never say never