Cabriolet Problems

[nickCR]

Hello All,
I am having some problems with my Cabriolet which i'm hoping some of you here may have resolved in the past and could help me resolve the issues.

Mechanical:

1. The car once warm all of a sudden started acting weird the other day. Once it would warm up the idle started to fluctuate between 300 & 1500 rpm. So I went to my mechanic and we turned up the idle, this fixed the problem, a day or two later the idle started doing the same thing but wasn't so bad as before. Then two nights ago it really started acting up and would simply stall at every stop. I took a bit of a fast drive on the high way. After the run the following day the car was being rather funny but in a really strange way. Instead of idling up & down now it was idling at 1200 - 1500 rpm which is no where near where it's set. (it's set at 600). This caused some concern ofcourse. The only problem I have had is that the cover on the mass air flow sensor was coming off so we put it back on with silicon. I don't think any water got in here so I really don't know what the issue would be. Any ideas?

2. The spedomoter doesn't work.

3. I changed the steering wheel. I had to do a bunch of mickey mouse stuff to change the wheel. Is there a piece I can put on the steering column that doesn't have the AirBag control installed but has the retractor for the signals and also a conection for the horn?

4. The air conditioning, heating system works but doesn't. It pushes out air on the right and left side but not out the center any ideas?

5. I put 16 inch rims with 205/50/16 tires. Everytime I hit a dip in the road or get agressive in corners it scrapes the lip around the wheel well. I was wondering if there is anything I can do other then getting into expensive suspension kits.

Pictures:

For those of you interested in taking a look at the car. I've included some pictures below.