Greetings from eastern Europe & a couple of questions

[Tyan]

  Hello fellow GS riders!

I know there is a thread for this purpose but first I would like to introduce myself while asking a few questions about my beloved GS in the process.
Now then... I'm 21 years old from Sofia, Bulgaria and I am currently studying Pharmacy with 5 more semesters to go. I ride a 97' GS as my second bike, before that I had an Aprilia AF Futura 125cc.  I am very happy with the Suzuki and although i've had it for more than a year, it still has much more to teach me. A friend bought and imported it from Germany for me, because I couldn't find a descent one here in Bulgaria. Oddly it is not a popular bike here and very few people own it. Maybe it's because people don't appreciate the practicality of the motorbike and think of it more as entertainment - that would explain the dominant number of GSXR, CBR, YZF etc bikes ridden, even by beginners. That's why I'm very grateful for this great messageboard!
Oh and a pic of me and my Suzi for those who are interested - http://bikepics.com/pictures/858734/

  So...on to the questions. It seems the bike had spent quite a lot of time in the suzuki dealership and it arrived with vintage 98' tyres. The sad part is that I am still running on those tyres, but I can't put it off any longer - I must get new rubbers!  The problem is that I can't find 130/70 17 size tyres, the 130 width is available only for enduro bikes.
I came across some Shinko radial tyres with sizes 110/70-R17 & 140/60 -R17 that seem affordable. The pair is roughly 200 USD. My only concern is wether the bike will be lowered too much by the rear tyre in comparison to the 130/70. There are a few 150/60 options, but i've been reading up on the rim issue and then there's the clearance problem. So, will 140/60 fit and not sacrifice handling?
   Second question. How many fingers do you use to engage the clutch? Until now I used 4 fingers and pulled it all the way to the handlebar, but today I realised it isn't necessary and by adjusting it I can easily use only 2 fingers or even one and pull it about half way.
   Third...
  Recently replaced the rear brake pads with supposedly quality ones - Vesrah, but they are screeching every time I use the brake. That's 2000Km since the change and they are still doing it. Is there a cure, or do I need new pads?
  Last...
I want to make my exaust louder for the purpose of being heard from further away by careless drivers. I read about drilling holes at the back of the pipe, but I understand it may require rejetting. The problems is I do not understand the concept of this task and most probably can't find someone with the tools (jet kit) to do it. Is it worth it or should I keep it the way it is?

  Thanks in advance to all of you, who will bother helping me out and please forgive me for any spelling errors & other mistakes. I'm a bit rusty you know...

[werase643]

welcome sir or mam.....

yeah the 140 should be fine
it will lower the seat....maybe 5-7mm at most

clutch...as you feel comfortable...whatever works for you is good

pads are probably glazed
if you can remove them....
remove
place onto concrete and scuff the friction material....like you are putting out a cig with your foot.

the ex sounds really crappy when you drill it

[starwalt]

Your English is excellent...and your American English is better than most here in the US. Bravo!

+1 to werase643 on the brake pads. The symptom you describe indicates glazing of the pad material. His suggestion is a practical and inexpensive. 

In regards to your clutch technique, official training by the MSF teaches covering the clutch with all four fingers for beginning riders. This is rarely done by racers and very experienced riders. Do what is safe and what you are comfortable with. (The MSF is a USA organization for motorcyle safety.)

A loud exhaust would probably be best obtained with a different exhaust. A different exhaust (aftermarket) will probably require a rejet of the carbs. Unless you are experienced at this, seek assistance.

Welcome to the world of GS!