Hey guys, just to start I dont know crap about cars and will be having a mechanic look into these issues just wondering if you guys can think of where the issue most likely is -

#1 misfire from 0-20 - it kind of chugs then stabilizes after the turbos spool a bit (recently upgraded to t25s) and drives alright after that
#2 squealing noise in low end - whether its cold or warmed up it makes a squealing noise in first gear that stops after second or if i let off the gas for a bit
#3 speedometer partially working - from 0-50 it works pretty accurately then it kind of stalls around 60 and jumps to 80 occasionally and sticks etc
#4 battery has died after slowing down quickly a couple times - I think there may be an electrical issue draining the battery that I will have to figure out... going to remove the stereo/subs and see if it helps

Thanks for any advice! I know this probably isnt enough information so if you have any questions post em up I'll check back frequently