no read more carefully: i have drum brakes all round and need to improve them.
You don't actually mention drums anywhere in your original post. You just say brakes so Gray was a valid question trying to get more information with which to offer the best advice.
So, now that we know you've got drum brakes, what do you mean, improve them? If you have a 998 fitted then properly adjusted, well maintained drum brakes should be perfectly adequate for standard road use. If you don't want the 'hassle' of adjusting them properly and regularly then, yes, as mentioned above it will cost you plenty to convert to discs. Attempting it yourself depends how confident you are that you know what you're doing. If not, add garage labour costs onto the price too.
8.4's you can pick up complete 2nd hand sets from about £50 (make sure you get the rear spacered drums). Always a good idea to fit new discs and pads unless you know where they have come from personally. Add another £25-30 to the price for that. You will need new front brake hoses as drum and disc ones are different lengths. Another £20 or so. You will also need new rear cylinders as the bore is different for drums and discs. Another £20 ish. So it's not THAT cheap. New kit to convert to 7.5's you're looking at in excess of £300 easily. Even 2nd hand 7.5 set ups are still expensive AND they will probably need a refurb.
All depends on your budget and your know-how.
The engine will quite often 'slow' when you switch on something which will be a major drain on power. A small dip is normal, anything more than that and you are probably overloading your system too much. How are the spots fitted? Do they have a separate relay/fuse? How are they wired in? Separate switch or wired into the headlights?
Yes, the accelerator cablecan become frayed and rub on the sheath. Check first that the sheath inside the engine bay isn't catching on anything and that you can slide the cable in and out manually. They're only a couple of quid anyway so if it looks like it might be sticking inside the sheath just replace it. If it IS sticking, you really don't want it to stick permanently with the throttle in the down position do you??
P.S. covering all your electrics with lots of WD40 will eventually have a detrimental effect. It should only be used in emergencies (ie damp starting etc). Clean all the fuse box and bullet connectors with sand paper then smear with grease or just plain old vaseline so keep the damp out.
