I am from Indian subcontinent. I have a JDM 1995 AE110 XE Saloon 1.5L on 5AFE engine, 90000 miles on the Odo. I use fully synthetic oil, Dexron III ATF, NGK G Power plug, OEM plug wires, distributor timing a little advanced. I'd seek suggestion on the following problems-

1. Front suspension feels hard, almost no rebound. they are VERY hard to push down and slight to almost no bounce. Could it be coil springs or struts? Struts changed 4 months ago (chinese brand, not expensive KYB Japan). Ball joint changed almost a year ago, Coil springs are at least 1 year old (previous owner changed them or not i have no idea). What could be wrong?

2. auto trans shifter is not smooth between shifting from P to R to N and the other way round, There is a light rough sound which shifting. the clutch (or whatever's called- the big button beside it) and the spring mechanism is also not smooth. OD button works ok but sometimes doesn't lock/unlock properly. Should I check the assembly or replace the shifter unit?

3. I have a powered subweefer (used for PC 2.1 system) sitting at home, can I hook it up somehow with my DVD navigation? Currently the car has a double DIN navigation system installed with 2 rear speaker, 2 side door speaker. There is a single DIN slot empty- looks odd. I got a gift of Sony Xplode single DIN mp3 player. Can I also install this player in my empty single DIN slot and connect the wiring? I mean is it possible to at least play one device at a time?

4. Is it normal for a car to lose some power when the AC is on?

5. will installing an aftermarket tailpipe attachment (show-pipe that attaches to the tip of tailpipe) affect torque?

Thanks guys