isues with the 633

i have a 1984 633 with over 300k miles on it....so here are my issues and questions...one, concidering how high the milage is, should i jst junk it? 2, in warm weather my car slows down SOOOOOOOO MUCH! like it takes 20 seconds to hit 60...and at night when its cold i feel like im driving a ferrarri...how do i fix this? and also my transmission has issues with shifting...sometimes i get a smooth shift and i barely accelerate...other times it kickes me in the ass and lets me know im its bitch and flies....how can i remedy this? and also i want my car to be able to compete with the big boys...so is it wise to supercharge it? and what is the cheapest horsepower upgrade i can get? and also my cars milage difers wildly...one time ill drive up to SF wich is an hour away and not use ne gas...another time ill use half a tank...again how do i fix this crud car? thanx 4 ur help

I guess the first question is [there always a question before an answer, isn't there?] HOW MUCH DO YOU REALLY LOVE THIS CAR??

I guess the first question is [there always a question before an answer, isn't there?] HOW MUCH DO YOU REALLY LOVE THIS CAR?? All of your issues can be rectified but when will your love/dollars come to an end?
300k isn't bad for one of these but even BMW's get tired, and now you want even more out of 'her/him'. If this car's all you'll have for a while, take it one step at a time but don't expect any miracles in power [ it will never be an M635 without spending enough on it to buy one]. You can sort out what you have, if you chose and make it a nice 'driver' again.
These are only my own humble opinions...I'll be checking back.........jb

yea i love my money...how ever little i have left (im kind broke caus i had to replace the tranny twice in one week) and i love my car...i want a car that turns heads, and roars by...and my car definetly roars by....and then loses its muffler about 20 yards down lol....how much does an m635 cost?