C483 Scalextric Jaguar XJ220
Well with Scalextric's 1990s (could be wrong here) release of Jaguar's XJ220 I've all but given up on it being released again by one of the big slot manufactures. Fortunately the Scalextric 1990s release is much better on the track than you might expect with just a few simple tweaks.
For pretty much a bargain I purchased my XJ220 second hand from ebay and decided quickly that the ugly wheels had to go. The original rubber was roack-hard so why not upgrade the wheels while I was at it?
My favourite replacement wheel at the moment is Ninco's Pro Race EVO magnesium, they seem to look good on cars from different periods (although I'm sure some will disagree with me).
You can purchase a full set of EVOs for around the $AU30 mark (plus another $10 for decent rubber) which might be a little rich for some. For me given the slot was less than $20 to start with, I was happy to spend the dollars. It's your choice regarding the upgrading of guide, braids, motor, axles and crown gear (all good performance improvements I sure) but I stuck with just the wheels and rubber with my XJ220.
With some of my other older slots I've dry brushed interior/exterior details such as dash boards, grills or exhaust and even added a more detailed driver figure (old driver figures can be pretty basic).
As you might expect on track performance and physics improvements are impressive. The car feels far more manageable to drive and runs considerably quieter around the track. For me the improved aesthetics justify the upgrade alone and I love the fact that I've upcycled an old favourite.