it will die eventually, some guys I know said they killed on with bolt-ons, others lasted a season or 2 at the strip with H/C swaps and then went. Essentially its the clutches and sunshell that go, as you can do a cheap and nasty clutch pack as get the tranny to last a bit longer. The guys at eatmyshift.com seem knowledgeable and gave me a quote of $2500 for late type 4L60E built to stand 700 hp with a 3500 stall (in US) there are UK specialist but im sure they put the 'american car' prices on ie 3x shipping it yourself
It you treat the tranny with respect, just normal pottering, not many WOT kickdowns and not too much racing, then it will last a bit longer...maybe
Basically as you will have read, the drive lines on the 4th gens are weak compared to the power the cars put down but there are dudes running stock diffs with supercharges, but dont race with slicks
In short, yes it will give up eventually, when is a matter of driving style. Also Chris, im sure your tranny might have had some work already, a shift kit or something with you mentioning the shift are harder??
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'99 Z28 A4, 253 LS2 heads, 228R TSP cam, Patriol Dual Springs, Double roller timing chain, LS6 ported oil pump, OBX LTs, 3" True Duals, LS6 intake, 42lb/hr injectors, SLP lid + bellow, EFIlive COS 3 Speed Denisty Tune (self tuned), 3200 Circle D stall, CAI mod, KYB AGXs, Eibach Pro Front Springs, UMI panhard, LCA + Brackets, Strut Brace, Custom Subframe connectors, WS6 axle with 3.42s, 18" American Racing Rebels, US mirrors, 93 tail lights, 3.5 inch custom cowl hood. Mickey T's Street DRs on Vette-ZR1 wheels for the strip !
Best ET: 12.0 @ 116 mph (on a 0-60ft of 1.8 s)